<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with Wdesk from Workiva-->
<!--Copyright 2023 Workiva-->
<!--r:17c899da-50df-4823-82c6-e2b75b745b1d,g:4736c9db-f024-4fd9-ba18-9f47f0ea2b15-->
<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member"/>
  <link:roleRef roleURI="http://www.gentex.com/role/ConsolidatedStatementsofShareholdersInvestment" xlink:type="simple" xlink:href="gntx-20221231.xsd#ConsolidatedStatementsofShareholdersInvestment"/>
  <link:definitionLink xlink:role="http://www.gentex.com/role/ConsolidatedStatementsofShareholdersInvestment" xlink:type="extended" id="if0881a9b30c44d97a2f6760a1fe40573_ConsolidatedStatementsofShareholdersInvestment">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_d0774211-eeb5-4906-a3d4-960e78f6ee62" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_4ea18c1b-d750-4f54-96d4-12ae97c71c75" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_d0774211-eeb5-4906-a3d4-960e78f6ee62" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_4ea18c1b-d750-4f54-96d4-12ae97c71c75" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_d1da378f-b8c6-4fb7-9d9c-325e37c3655a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_4ea18c1b-d750-4f54-96d4-12ae97c71c75" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_d1da378f-b8c6-4fb7-9d9c-325e37c3655a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_b0e148c6-2e70-4d6c-a25d-98c00b1faf6d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_4ea18c1b-d750-4f54-96d4-12ae97c71c75" xlink:to="loc_us-gaap_StockholdersEquity_b0e148c6-2e70-4d6c-a25d-98c00b1faf6d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_88690c54-1042-4f4b-94f8-1a80f45eb1c2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_4ea18c1b-d750-4f54-96d4-12ae97c71c75" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_88690c54-1042-4f4b-94f8-1a80f45eb1c2" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues_36068b72-eea7-4c89-9a0f-dae005b1441d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockIssuedDuringPeriodValueNewIssues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_4ea18c1b-d750-4f54-96d4-12ae97c71c75" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues_36068b72-eea7-4c89-9a0f-dae005b1441d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesAcquisitions_1cf71ade-32a4-4b0b-8593-0295a368c887" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockIssuedDuringPeriodSharesAcquisitions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_4ea18c1b-d750-4f54-96d4-12ae97c71c75" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesAcquisitions_1cf71ade-32a4-4b0b-8593-0295a368c887" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueAcquisitions_160ba517-1193-40c8-b961-1821f3e031a7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockIssuedDuringPeriodValueAcquisitions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_4ea18c1b-d750-4f54-96d4-12ae97c71c75" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueAcquisitions_160ba517-1193-40c8-b961-1821f3e031a7" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchasedDuringPeriodShares_fb534290-82a4-4fbf-9c76-73060e02aa88" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockRepurchasedDuringPeriodShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_4ea18c1b-d750-4f54-96d4-12ae97c71c75" xlink:to="loc_us-gaap_StockRepurchasedDuringPeriodShares_fb534290-82a4-4fbf-9c76-73060e02aa88" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchasedDuringPeriodValue_9208f56a-e740-4fa6-b788-c07dee2fd53b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockRepurchasedDuringPeriodValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_4ea18c1b-d750-4f54-96d4-12ae97c71c75" xlink:to="loc_us-gaap_StockRepurchasedDuringPeriodValue_9208f56a-e740-4fa6-b788-c07dee2fd53b" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_b3ae11a6-2045-483c-b4d6-fd0adb7c3761" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_4ea18c1b-d750-4f54-96d4-12ae97c71c75" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_b3ae11a6-2045-483c-b4d6-fd0adb7c3761" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsCommonStockCash_022c11b7-09c5-4991-b5b1-a78260ef11f5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DividendsCommonStockCash"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_4ea18c1b-d750-4f54-96d4-12ae97c71c75" xlink:to="loc_us-gaap_DividendsCommonStockCash_022c11b7-09c5-4991-b5b1-a78260ef11f5" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_ef1a6678-b848-458e-8641-df8204f68c8e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_4ea18c1b-d750-4f54-96d4-12ae97c71c75" xlink:to="loc_us-gaap_NetIncomeLoss_ef1a6678-b848-458e-8641-df8204f68c8e" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_915b2c9a-4a23-41c0-a14d-260dd66f49fc" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_4ea18c1b-d750-4f54-96d4-12ae97c71c75" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_915b2c9a-4a23-41c0-a14d-260dd66f49fc" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_0d413d1d-60df-42ac-b2f3-dd1ed820c4c0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_ce68c748-d505-4b45-838d-d34315651782" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockholdersEquity"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_be8879f5-0eba-475f-aff3-2d1e401d19cd" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_d0774211-eeb5-4906-a3d4-960e78f6ee62" xlink:to="loc_us-gaap_StatementTable_be8879f5-0eba-475f-aff3-2d1e401d19cd" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_76493131-6b6d-4b05-92cd-7c3067fb22f7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_be8879f5-0eba-475f-aff3-2d1e401d19cd" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_76493131-6b6d-4b05-92cd-7c3067fb22f7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_76493131-6b6d-4b05-92cd-7c3067fb22f7_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_76493131-6b6d-4b05-92cd-7c3067fb22f7" xlink:to="loc_us-gaap_EquityComponentDomain_76493131-6b6d-4b05-92cd-7c3067fb22f7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_8a4dcda1-0c84-4f57-9c23-74324691b791" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_76493131-6b6d-4b05-92cd-7c3067fb22f7" xlink:to="loc_us-gaap_EquityComponentDomain_8a4dcda1-0c84-4f57-9c23-74324691b791" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_6ae006a0-9489-4415-8795-88169e709b83" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_8a4dcda1-0c84-4f57-9c23-74324691b791" xlink:to="loc_us-gaap_CommonStockMember_6ae006a0-9489-4415-8795-88169e709b83" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_f53806b9-bef7-4ca7-b180-1e771014aff7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AdditionalPaidInCapitalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_8a4dcda1-0c84-4f57-9c23-74324691b791" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_f53806b9-bef7-4ca7-b180-1e771014aff7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_78e30f57-5cf8-4e33-887f-19957610dea4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RetainedEarningsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_8a4dcda1-0c84-4f57-9c23-74324691b791" xlink:to="loc_us-gaap_RetainedEarningsMember_78e30f57-5cf8-4e33-887f-19957610dea4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_264bacb0-649c-48f0-b7b0-165e74f9c558" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_8a4dcda1-0c84-4f57-9c23-74324691b791" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_264bacb0-649c-48f0-b7b0-165e74f9c558" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gentex.com/role/SummaryofSignificantAccountingandReportingPoliciesScheduleofAllowanceforDoubtfulAccountsDetails" xlink:type="simple" xlink:href="gntx-20221231.xsd#SummaryofSignificantAccountingandReportingPoliciesScheduleofAllowanceforDoubtfulAccountsDetails"/>
  <link:definitionLink xlink:role="http://www.gentex.com/role/SummaryofSignificantAccountingandReportingPoliciesScheduleofAllowanceforDoubtfulAccountsDetails" xlink:type="extended" id="i35d8bd51d8e948b6bed060c675f060cd_SummaryofSignificantAccountingandReportingPoliciesScheduleofAllowanceforDoubtfulAccountsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_srt_ValuationAndQualifyingAccountsDisclosureLineItems_bf014023-de1d-4af2-a462-af1bd69cfa80" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ValuationAndQualifyingAccountsDisclosureLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MovementInValuationAllowancesAndReservesRollForward_4a2fbc6c-452e-4a26-bb62-4b83e2814422" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_MovementInValuationAllowancesAndReservesRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ValuationAndQualifyingAccountsDisclosureLineItems_bf014023-de1d-4af2-a462-af1bd69cfa80" xlink:to="loc_us-gaap_MovementInValuationAllowancesAndReservesRollForward_4a2fbc6c-452e-4a26-bb62-4b83e2814422" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesBalance_efea3511-2f98-428f-8dd8-6302a019c575" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ValuationAllowancesAndReservesBalance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MovementInValuationAllowancesAndReservesRollForward_4a2fbc6c-452e-4a26-bb62-4b83e2814422" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesBalance_efea3511-2f98-428f-8dd8-6302a019c575" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesChargedToCostAndExpense_1b141e5e-5e4b-4865-ac22-ec3957acca84" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ValuationAllowancesAndReservesChargedToCostAndExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MovementInValuationAllowancesAndReservesRollForward_4a2fbc6c-452e-4a26-bb62-4b83e2814422" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesChargedToCostAndExpense_1b141e5e-5e4b-4865-ac22-ec3957acca84" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesAdjustments_897ac066-0b32-448a-b306-5758bb156b89" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ValuationAllowancesAndReservesAdjustments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MovementInValuationAllowancesAndReservesRollForward_4a2fbc6c-452e-4a26-bb62-4b83e2814422" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesAdjustments_897ac066-0b32-448a-b306-5758bb156b89" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesBalance_b0795c16-48d0-40f7-b929-6bbe7267c75d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ValuationAllowancesAndReservesBalance"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ValuationAndQualifyingAccountsDisclosureTable_8e8a5571-0426-4bc1-8cf2-f248c8ee0fbd" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ValuationAndQualifyingAccountsDisclosureTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_srt_ValuationAndQualifyingAccountsDisclosureLineItems_bf014023-de1d-4af2-a462-af1bd69cfa80" xlink:to="loc_srt_ValuationAndQualifyingAccountsDisclosureTable_8e8a5571-0426-4bc1-8cf2-f248c8ee0fbd" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesTypeAxis_3143f838-0323-493e-806a-1e0b8622d057" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ValuationAllowancesAndReservesTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_srt_ValuationAndQualifyingAccountsDisclosureTable_8e8a5571-0426-4bc1-8cf2-f248c8ee0fbd" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesTypeAxis_3143f838-0323-493e-806a-1e0b8622d057" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesDomain_3143f838-0323-493e-806a-1e0b8622d057_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ValuationAllowancesAndReservesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ValuationAllowancesAndReservesTypeAxis_3143f838-0323-493e-806a-1e0b8622d057" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesDomain_3143f838-0323-493e-806a-1e0b8622d057_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesDomain_bdf7917b-a0f8-42c8-87b2-b23fbffe852f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ValuationAllowancesAndReservesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ValuationAllowancesAndReservesTypeAxis_3143f838-0323-493e-806a-1e0b8622d057" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesDomain_bdf7917b-a0f8-42c8-87b2-b23fbffe852f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllowanceForCreditLossMember_d3176792-7935-4ca4-9688-cb5b02c889bc" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AllowanceForCreditLossMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ValuationAllowancesAndReservesDomain_bdf7917b-a0f8-42c8-87b2-b23fbffe852f" xlink:to="loc_us-gaap_AllowanceForCreditLossMember_d3176792-7935-4ca4-9688-cb5b02c889bc" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gentex.com/role/SummaryofSignificantAccountingandReportingPoliciesNarrativeDetails" xlink:type="simple" xlink:href="gntx-20221231.xsd#SummaryofSignificantAccountingandReportingPoliciesNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.gentex.com/role/SummaryofSignificantAccountingandReportingPoliciesNarrativeDetails" xlink:type="extended" id="ie197686cecf6465a9ddf4f5a9399273c_SummaryofSignificantAccountingandReportingPoliciesNarrativeDetails">
    <link:loc xlink:type="locator" xlink:label="loc_gntx_SummaryOfSignificantAccountingAndReportingPoliciesLineItems_058ad561-0721-41bf-8f50-35ed345c9f96" xlink:href="gntx-20221231.xsd#gntx_SummaryOfSignificantAccountingAndReportingPoliciesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_b74770dd-fcba-4313-94f6-c1f94cf9368d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityMethodInvestmentOwnershipPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_gntx_SummaryOfSignificantAccountingAndReportingPoliciesLineItems_058ad561-0721-41bf-8f50-35ed345c9f96" xlink:to="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_b74770dd-fcba-4313-94f6-c1f94cf9368d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestments_c04db7c1-02f7-4c18-ac29-fb982f3e4907" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_gntx_SummaryOfSignificantAccountingAndReportingPoliciesLineItems_058ad561-0721-41bf-8f50-35ed345c9f96" xlink:to="loc_us-gaap_EquityMethodInvestments_c04db7c1-02f7-4c18-ac29-fb982f3e4907" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesFvNiCurrentAndNoncurrent_163f12be-46c8-407d-8246-cc5230f591cd" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquitySecuritiesFvNiCurrentAndNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_gntx_SummaryOfSignificantAccountingAndReportingPoliciesLineItems_058ad561-0721-41bf-8f50-35ed345c9f96" xlink:to="loc_us-gaap_EquitySecuritiesFvNiCurrentAndNoncurrent_163f12be-46c8-407d-8246-cc5230f591cd" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireEquityMethodInvestments_f9d39ed5-f08b-4c7f-8361-dec059903bd5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PaymentsToAcquireEquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_gntx_SummaryOfSignificantAccountingAndReportingPoliciesLineItems_058ad561-0721-41bf-8f50-35ed345c9f96" xlink:to="loc_us-gaap_PaymentsToAcquireEquityMethodInvestments_f9d39ed5-f08b-4c7f-8361-dec059903bd5" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockValue_904648c6-0a20-4cc6-b894-d882c51828bc" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommonStockValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_gntx_SummaryOfSignificantAccountingAndReportingPoliciesLineItems_058ad561-0721-41bf-8f50-35ed345c9f96" xlink:to="loc_us-gaap_CommonStockValue_904648c6-0a20-4cc6-b894-d882c51828bc" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueAmount_a9f9b0e1-1e2d-4f0c-9c0f-fcfe3299acc6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_gntx_SummaryOfSignificantAccountingAndReportingPoliciesLineItems_058ad561-0721-41bf-8f50-35ed345c9f96" xlink:to="loc_us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueAmount_a9f9b0e1-1e2d-4f0c-9c0f-fcfe3299acc6" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermInvestments_63554437-1617-4a5a-9044-c66f9edb037b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortTermInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_gntx_SummaryOfSignificantAccountingAndReportingPoliciesLineItems_058ad561-0721-41bf-8f50-35ed345c9f96" xlink:to="loc_us-gaap_ShortTermInvestments_63554437-1617-4a5a-9044-c66f9edb037b" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermInvestments_1002234e-389b-480d-8bde-8959e5a501e5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongTermInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_gntx_SummaryOfSignificantAccountingAndReportingPoliciesLineItems_058ad561-0721-41bf-8f50-35ed345c9f96" xlink:to="loc_us-gaap_LongTermInvestments_1002234e-389b-480d-8bde-8959e5a501e5" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_AllowanceForObsoleteAndSlowMovingInventories_b9551d0d-50ea-4abe-9270-40512fed6697" xlink:href="gntx-20221231.xsd#gntx_AllowanceForObsoleteAndSlowMovingInventories"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_gntx_SummaryOfSignificantAccountingAndReportingPoliciesLineItems_058ad561-0721-41bf-8f50-35ed345c9f96" xlink:to="loc_gntx_AllowanceForObsoleteAndSlowMovingInventories_b9551d0d-50ea-4abe-9270-40512fed6697" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_db863c60-ca91-45fe-950c-0adf84b66f37" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_gntx_SummaryOfSignificantAccountingAndReportingPoliciesLineItems_058ad561-0721-41bf-8f50-35ed345c9f96" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_db863c60-ca91-45fe-950c-0adf84b66f37" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Depreciation_e2c8a54c-d198-4fb7-9322-87daca2ff9f9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_Depreciation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_gntx_SummaryOfSignificantAccountingAndReportingPoliciesLineItems_058ad561-0721-41bf-8f50-35ed345c9f96" xlink:to="loc_us-gaap_Depreciation_e2c8a54c-d198-4fb7-9322-87daca2ff9f9" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_AccountPayableCapitalExpenditures_590327d2-6622-4701-94ce-b80054719577" xlink:href="gntx-20221231.xsd#gntx_AccountPayableCapitalExpenditures"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_gntx_SummaryOfSignificantAccountingAndReportingPoliciesLineItems_058ad561-0721-41bf-8f50-35ed345c9f96" xlink:to="loc_gntx_AccountPayableCapitalExpenditures_590327d2-6622-4701-94ce-b80054719577" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MarketingAndAdvertisingExpense_191cdc6b-4f45-4c10-8bd8-36aceda0eb76" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_MarketingAndAdvertisingExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_gntx_SummaryOfSignificantAccountingAndReportingPoliciesLineItems_058ad561-0721-41bf-8f50-35ed345c9f96" xlink:to="loc_us-gaap_MarketingAndAdvertisingExpense_191cdc6b-4f45-4c10-8bd8-36aceda0eb76" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfPropertyRepairsAndMaintenance_5fd64828-08be-4c6b-9f68-68f74aadc78f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CostOfPropertyRepairsAndMaintenance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_gntx_SummaryOfSignificantAccountingAndReportingPoliciesLineItems_058ad561-0721-41bf-8f50-35ed345c9f96" xlink:to="loc_us-gaap_CostOfPropertyRepairsAndMaintenance_5fd64828-08be-4c6b-9f68-68f74aadc78f" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiabilityStatementOfFinancialPositionExtensibleList_f19afac9-b8e1-4673-8556-693e392672a9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingLeaseLiabilityStatementOfFinancialPositionExtensibleList"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_gntx_SummaryOfSignificantAccountingAndReportingPoliciesLineItems_058ad561-0721-41bf-8f50-35ed345c9f96" xlink:to="loc_us-gaap_OperatingLeaseLiabilityStatementOfFinancialPositionExtensibleList_f19afac9-b8e1-4673-8556-693e392672a9" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseRemainingLeaseTerm_facfe42a-5e99-4177-bafd-6435215a21b9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LesseeOperatingLeaseRemainingLeaseTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_gntx_SummaryOfSignificantAccountingAndReportingPoliciesLineItems_058ad561-0721-41bf-8f50-35ed345c9f96" xlink:to="loc_us-gaap_LesseeOperatingLeaseRemainingLeaseTerm_facfe42a-5e99-4177-bafd-6435215a21b9" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1_9c5446f3-5e61-4380-aee4-b72050d5b28a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_gntx_SummaryOfSignificantAccountingAndReportingPoliciesLineItems_058ad561-0721-41bf-8f50-35ed345c9f96" xlink:to="loc_us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1_9c5446f3-5e61-4380-aee4-b72050d5b28a" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent_9b50b829-0d6d-41c3-9e9b-f6f9f7849b3d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_gntx_SummaryOfSignificantAccountingAndReportingPoliciesLineItems_058ad561-0721-41bf-8f50-35ed345c9f96" xlink:to="loc_us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent_9b50b829-0d6d-41c3-9e9b-f6f9f7849b3d" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_3ce945d2-6d6b-4cd1-90db-8ca7f6e45178" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_gntx_SummaryOfSignificantAccountingAndReportingPoliciesLineItems_058ad561-0721-41bf-8f50-35ed345c9f96" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_3ce945d2-6d6b-4cd1-90db-8ca7f6e45178" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_SharebasedCompensationArrangementbySharebasedPaymentAwardNumberofPlans_2316733e-838e-44e3-ba67-e729f74ef4e2" xlink:href="gntx-20221231.xsd#gntx_SharebasedCompensationArrangementbySharebasedPaymentAwardNumberofPlans"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_gntx_SummaryOfSignificantAccountingAndReportingPoliciesLineItems_058ad561-0721-41bf-8f50-35ed345c9f96" xlink:to="loc_gntx_SharebasedCompensationArrangementbySharebasedPaymentAwardNumberofPlans_2316733e-838e-44e3-ba67-e729f74ef4e2" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_SummaryofSignificantAccountingandReportingPoliciesTable_fbd96380-28ca-4cd4-94a4-4be6f6649dda" xlink:href="gntx-20221231.xsd#gntx_SummaryofSignificantAccountingandReportingPoliciesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_gntx_SummaryOfSignificantAccountingAndReportingPoliciesLineItems_058ad561-0721-41bf-8f50-35ed345c9f96" xlink:to="loc_gntx_SummaryofSignificantAccountingandReportingPoliciesTable_fbd96380-28ca-4cd4-94a4-4be6f6649dda" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_1f38162d-5085-4f14-b980-c0390914d9b1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_gntx_SummaryofSignificantAccountingandReportingPoliciesTable_fbd96380-28ca-4cd4-94a4-4be6f6649dda" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_1f38162d-5085-4f14-b980-c0390914d9b1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_1f38162d-5085-4f14-b980-c0390914d9b1_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_1f38162d-5085-4f14-b980-c0390914d9b1" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_1f38162d-5085-4f14-b980-c0390914d9b1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_29f62911-aa5f-4e28-9a78-f151445e8b0f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_1f38162d-5085-4f14-b980-c0390914d9b1" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_29f62911-aa5f-4e28-9a78-f151445e8b0f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BuildingAndBuildingImprovementsMember_e045515a-bbda-43ed-a4b2-663d869de1b7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BuildingAndBuildingImprovementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_29f62911-aa5f-4e28-9a78-f151445e8b0f" xlink:to="loc_us-gaap_BuildingAndBuildingImprovementsMember_e045515a-bbda-43ed-a4b2-663d869de1b7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MachineryAndEquipmentMember_04858e2d-422f-4084-88d6-99fa1f3e6c15" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_MachineryAndEquipmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_29f62911-aa5f-4e28-9a78-f151445e8b0f" xlink:to="loc_us-gaap_MachineryAndEquipmentMember_04858e2d-422f-4084-88d6-99fa1f3e6c15" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_c9c75b17-b3fc-477d-8356-0d504f2190bd" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_gntx_SummaryofSignificantAccountingandReportingPoliciesTable_fbd96380-28ca-4cd4-94a4-4be6f6649dda" xlink:to="loc_srt_RangeAxis_c9c75b17-b3fc-477d-8356-0d504f2190bd" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_c9c75b17-b3fc-477d-8356-0d504f2190bd_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_c9c75b17-b3fc-477d-8356-0d504f2190bd" xlink:to="loc_srt_RangeMember_c9c75b17-b3fc-477d-8356-0d504f2190bd_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_94736393-fd7c-4d71-9f2e-5bd858cfb9c2" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_c9c75b17-b3fc-477d-8356-0d504f2190bd" xlink:to="loc_srt_RangeMember_94736393-fd7c-4d71-9f2e-5bd858cfb9c2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_e5223d6e-35e6-4bc6-9ac8-e6f62a02f745" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_94736393-fd7c-4d71-9f2e-5bd858cfb9c2" xlink:to="loc_srt_MinimumMember_e5223d6e-35e6-4bc6-9ac8-e6f62a02f745" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_2e8325be-e018-44e8-b96e-77899aa265ee" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_94736393-fd7c-4d71-9f2e-5bd858cfb9c2" xlink:to="loc_srt_MaximumMember_2e8325be-e018-44e8-b96e-77899aa265ee" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_96a4fff6-8152-43a7-9556-b52afc1d6ca0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_gntx_SummaryofSignificantAccountingandReportingPoliciesTable_fbd96380-28ca-4cd4-94a4-4be6f6649dda" xlink:to="loc_us-gaap_AwardTypeAxis_96a4fff6-8152-43a7-9556-b52afc1d6ca0" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_96a4fff6-8152-43a7-9556-b52afc1d6ca0_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_96a4fff6-8152-43a7-9556-b52afc1d6ca0" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_96a4fff6-8152-43a7-9556-b52afc1d6ca0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_fcf278db-af5b-48d2-b04d-a063ef5f6957" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_96a4fff6-8152-43a7-9556-b52afc1d6ca0" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_fcf278db-af5b-48d2-b04d-a063ef5f6957" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockOptionMember_ed6bae31-5807-4be0-aadd-d2655b841feb" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EmployeeStockOptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_fcf278db-af5b-48d2-b04d-a063ef5f6957" xlink:to="loc_us-gaap_EmployeeStockOptionMember_ed6bae31-5807-4be0-aadd-d2655b841feb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockMember_542cd631-90c7-4c97-8674-55732a1d1b5e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EmployeeStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_fcf278db-af5b-48d2-b04d-a063ef5f6957" xlink:to="loc_us-gaap_EmployeeStockMember_542cd631-90c7-4c97-8674-55732a1d1b5e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_de0e518b-b094-43e7-90e7-ceb6f785548c" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_gntx_SummaryofSignificantAccountingandReportingPoliciesTable_fbd96380-28ca-4cd4-94a4-4be6f6649dda" xlink:to="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_de0e518b-b094-43e7-90e7-ceb6f785548c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_de0e518b-b094-43e7-90e7-ceb6f785548c_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_EquityMethodInvesteeNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_de0e518b-b094-43e7-90e7-ceb6f785548c" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_de0e518b-b094-43e7-90e7-ceb6f785548c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_725692f9-8064-439f-9f3f-814f4de28b90" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_EquityMethodInvesteeNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_de0e518b-b094-43e7-90e7-ceb6f785548c" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_725692f9-8064-439f-9f3f-814f4de28b90" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_GentexCorporationMember_f8c59e54-55c5-4fcf-bcb5-1e645874a91e" xlink:href="gntx-20221231.xsd#gntx_GentexCorporationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_725692f9-8064-439f-9f3f-814f4de28b90" xlink:to="loc_gntx_GentexCorporationMember_f8c59e54-55c5-4fcf-bcb5-1e645874a91e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_GreenMarblesMember_a150f4a1-7daa-4f0e-a70e-98e6fa27969a" xlink:href="gntx-20221231.xsd#gntx_GreenMarblesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_725692f9-8064-439f-9f3f-814f4de28b90" xlink:to="loc_gntx_GreenMarblesMember_a150f4a1-7daa-4f0e-a70e-98e6fa27969a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_131a3375-95ed-4e1c-bb02-5dc6ba7e6088" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_gntx_SummaryofSignificantAccountingandReportingPoliciesTable_fbd96380-28ca-4cd4-94a4-4be6f6649dda" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_131a3375-95ed-4e1c-bb02-5dc6ba7e6088" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_131a3375-95ed-4e1c-bb02-5dc6ba7e6088_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_131a3375-95ed-4e1c-bb02-5dc6ba7e6088" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_131a3375-95ed-4e1c-bb02-5dc6ba7e6088_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_d2ed6f1c-9c96-4f85-8e07-b54d86a01442" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_131a3375-95ed-4e1c-bb02-5dc6ba7e6088" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_d2ed6f1c-9c96-4f85-8e07-b54d86a01442" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermInvestmentsMember_49ce4d36-ba91-4b20-94f5-a83da4d01471" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortTermInvestmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_d2ed6f1c-9c96-4f85-8e07-b54d86a01442" xlink:to="loc_us-gaap_ShortTermInvestmentsMember_49ce4d36-ba91-4b20-94f5-a83da4d01471" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_LongTermInvestmentsMember_5329c7f7-15c5-4c78-81e7-58a54b5d4e63" xlink:href="gntx-20221231.xsd#gntx_LongTermInvestmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_d2ed6f1c-9c96-4f85-8e07-b54d86a01442" xlink:to="loc_gntx_LongTermInvestmentsMember_5329c7f7-15c5-4c78-81e7-58a54b5d4e63" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gentex.com/role/SummaryofSignificantAccountingandReportingPoliciesScheduleofAssetsorLiabilitiesHavingRecurringMeasurementsDetails" xlink:type="simple" xlink:href="gntx-20221231.xsd#SummaryofSignificantAccountingandReportingPoliciesScheduleofAssetsorLiabilitiesHavingRecurringMeasurementsDetails"/>
  <link:definitionLink xlink:role="http://www.gentex.com/role/SummaryofSignificantAccountingandReportingPoliciesScheduleofAssetsorLiabilitiesHavingRecurringMeasurementsDetails" xlink:type="extended" id="i4adf5079b9744bed8129b6aa620e793f_SummaryofSignificantAccountingandReportingPoliciesScheduleofAssetsorLiabilitiesHavingRecurringMeasurementsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_b6539d84-e693-481c-a344-1c0fa00a449a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_3ebcb8b2-2db6-426c-b92c-e33a62a7ced2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CashAndCashEquivalentsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_b6539d84-e693-481c-a344-1c0fa00a449a" xlink:to="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_3ebcb8b2-2db6-426c-b92c-e33a62a7ced2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_RestrictedCashFairValueDisclosure_a80c5339-bb26-4db8-99dd-3514718f5e64" xlink:href="gntx-20221231.xsd#gntx_RestrictedCashFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_b6539d84-e693-481c-a344-1c0fa00a449a" xlink:to="loc_gntx_RestrictedCashFairValueDisclosure_a80c5339-bb26-4db8-99dd-3514718f5e64" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentsFairValueDisclosure_b55a6c12-1e8c-4afe-af19-de74ab286582" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InvestmentsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_b6539d84-e693-481c-a344-1c0fa00a449a" xlink:to="loc_us-gaap_InvestmentsFairValueDisclosure_b55a6c12-1e8c-4afe-af19-de74ab286582" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentsAndCash_ea9bca5c-e0a4-4c0b-929d-c0d76333ea25" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InvestmentsAndCash"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_b6539d84-e693-481c-a344-1c0fa00a449a" xlink:to="loc_us-gaap_InvestmentsAndCash_ea9bca5c-e0a4-4c0b-929d-c0d76333ea25" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_1cf3599a-ecfd-4be2-b3bf-8e4108082e98" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_b6539d84-e693-481c-a344-1c0fa00a449a" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_1cf3599a-ecfd-4be2-b3bf-8e4108082e98" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeAxis_f23154d5-bd7f-42e2-b31a-fd6a9d7e46b5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InvestmentTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_1cf3599a-ecfd-4be2-b3bf-8e4108082e98" xlink:to="loc_us-gaap_InvestmentTypeAxis_f23154d5-bd7f-42e2-b31a-fd6a9d7e46b5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeCategorizationMember_f23154d5-bd7f-42e2-b31a-fd6a9d7e46b5_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InvestmentTypeCategorizationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_InvestmentTypeAxis_f23154d5-bd7f-42e2-b31a-fd6a9d7e46b5" xlink:to="loc_us-gaap_InvestmentTypeCategorizationMember_f23154d5-bd7f-42e2-b31a-fd6a9d7e46b5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeCategorizationMember_b09d5fd4-3c8d-4c09-a894-33995aeaead8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InvestmentTypeCategorizationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_InvestmentTypeAxis_f23154d5-bd7f-42e2-b31a-fd6a9d7e46b5" xlink:to="loc_us-gaap_InvestmentTypeCategorizationMember_b09d5fd4-3c8d-4c09-a894-33995aeaead8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermInvestmentsMember_a706139c-8172-4680-a041-90db1e929d73" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortTermInvestmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentTypeCategorizationMember_b09d5fd4-3c8d-4c09-a894-33995aeaead8" xlink:to="loc_us-gaap_ShortTermInvestmentsMember_a706139c-8172-4680-a041-90db1e929d73" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLongTermInvestmentsMember_ea167cbf-27c3-4efe-a50c-4f88617fee89" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherLongTermInvestmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentTypeCategorizationMember_b09d5fd4-3c8d-4c09-a894-33995aeaead8" xlink:to="loc_us-gaap_OtherLongTermInvestmentsMember_ea167cbf-27c3-4efe-a50c-4f88617fee89" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_721a75b8-382a-4116-86f6-b0ee7b8cd394" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_1cf3599a-ecfd-4be2-b3bf-8e4108082e98" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_721a75b8-382a-4116-86f6-b0ee7b8cd394" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_721a75b8-382a-4116-86f6-b0ee7b8cd394_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_721a75b8-382a-4116-86f6-b0ee7b8cd394" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_721a75b8-382a-4116-86f6-b0ee7b8cd394_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_51062ac1-2290-4c7a-91d7-fe87b5e636ae" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_721a75b8-382a-4116-86f6-b0ee7b8cd394" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_51062ac1-2290-4c7a-91d7-fe87b5e636ae" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_e81e5bc3-38e6-47cc-a079-b3a58e6e4025" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_51062ac1-2290-4c7a-91d7-fe87b5e636ae" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_e81e5bc3-38e6-47cc-a079-b3a58e6e4025" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_61f00956-e6aa-47d1-842e-506f71ba136f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_51062ac1-2290-4c7a-91d7-fe87b5e636ae" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_61f00956-e6aa-47d1-842e-506f71ba136f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_b447ad02-4f35-470c-b214-55fcb8de1f67" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_51062ac1-2290-4c7a-91d7-fe87b5e636ae" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_b447ad02-4f35-470c-b214-55fcb8de1f67" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_877c6207-6c06-4d7f-9458-c8f36334de61" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_1cf3599a-ecfd-4be2-b3bf-8e4108082e98" xlink:to="loc_us-gaap_FinancialInstrumentAxis_877c6207-6c06-4d7f-9458-c8f36334de61" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_877c6207-6c06-4d7f-9458-c8f36334de61_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_877c6207-6c06-4d7f-9458-c8f36334de61" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_877c6207-6c06-4d7f-9458-c8f36334de61_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_fc8f550e-d3fa-4bce-8e2d-c08012f609a9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_877c6207-6c06-4d7f-9458-c8f36334de61" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_fc8f550e-d3fa-4bce-8e2d-c08012f609a9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetBackedSecuritiesMember_f7d1e1b1-81a6-4a03-aa36-c0eb30c69be2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AssetBackedSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_fc8f550e-d3fa-4bce-8e2d-c08012f609a9" xlink:to="loc_us-gaap_AssetBackedSecuritiesMember_f7d1e1b1-81a6-4a03-aa36-c0eb30c69be2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CertificatesOfDepositMember_aa869ad3-837b-43c4-ae9e-a3fc15863195" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CertificatesOfDepositMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_fc8f550e-d3fa-4bce-8e2d-c08012f609a9" xlink:to="loc_us-gaap_CertificatesOfDepositMember_aa869ad3-837b-43c4-ae9e-a3fc15863195" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateBondSecuritiesMember_07d5f66d-6abe-49b9-834d-f1c42447cbb0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CorporateBondSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_fc8f550e-d3fa-4bce-8e2d-c08012f609a9" xlink:to="loc_us-gaap_CorporateBondSecuritiesMember_07d5f66d-6abe-49b9-834d-f1c42447cbb0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USGovernmentAgenciesDebtSecuritiesMember_198114b1-5e09-44cb-a340-b0ddd53214ce" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_USGovernmentAgenciesDebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_fc8f550e-d3fa-4bce-8e2d-c08012f609a9" xlink:to="loc_us-gaap_USGovernmentAgenciesDebtSecuritiesMember_198114b1-5e09-44cb-a340-b0ddd53214ce" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MunicipalBondsMember_10513c55-d7e7-4c72-9855-f92fb248f7e9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_MunicipalBondsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_fc8f550e-d3fa-4bce-8e2d-c08012f609a9" xlink:to="loc_us-gaap_MunicipalBondsMember_10513c55-d7e7-4c72-9855-f92fb248f7e9" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherDebtSecuritiesMember_d9db46bb-169d-4312-853a-8bc64ba724eb" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherDebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_fc8f550e-d3fa-4bce-8e2d-c08012f609a9" xlink:to="loc_us-gaap_OtherDebtSecuritiesMember_d9db46bb-169d-4312-853a-8bc64ba724eb" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_c680f7f1-6185-4cac-9c0b-0bc79b70f14e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_1cf3599a-ecfd-4be2-b3bf-8e4108082e98" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_c680f7f1-6185-4cac-9c0b-0bc79b70f14e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_c680f7f1-6185-4cac-9c0b-0bc79b70f14e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_c680f7f1-6185-4cac-9c0b-0bc79b70f14e" xlink:to="loc_us-gaap_EquityComponentDomain_c680f7f1-6185-4cac-9c0b-0bc79b70f14e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_d1abba6a-4a9d-44d4-b2f4-9d10c875c35e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_c680f7f1-6185-4cac-9c0b-0bc79b70f14e" xlink:to="loc_us-gaap_EquityComponentDomain_d1abba6a-4a9d-44d4-b2f4-9d10c875c35e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_65e48d23-49f5-4c98-af22-6bae322df645" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_d1abba6a-4a9d-44d4-b2f4-9d10c875c35e" xlink:to="loc_us-gaap_CommonStockMember_65e48d23-49f5-4c98-af22-6bae322df645" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gentex.com/role/SummaryofSignificantAccountingandReportingPoliciesScheduleofAmortizedCostUnrealizedGainsandLossesandMarketValueofInvestmentSecuritiesDetails" xlink:type="simple" xlink:href="gntx-20221231.xsd#SummaryofSignificantAccountingandReportingPoliciesScheduleofAmortizedCostUnrealizedGainsandLossesandMarketValueofInvestmentSecuritiesDetails"/>
  <link:definitionLink xlink:role="http://www.gentex.com/role/SummaryofSignificantAccountingandReportingPoliciesScheduleofAmortizedCostUnrealizedGainsandLossesandMarketValueofInvestmentSecuritiesDetails" xlink:type="extended" id="i537fd34140b24c0f879b40d2868c9a17_SummaryofSignificantAccountingandReportingPoliciesScheduleofAmortizedCostUnrealizedGainsandLossesandMarketValueofInvestmentSecuritiesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_722563a9-e38b-4c13-853c-91f46fd37956" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis_8da42729-1562-4ed0-846c-41a9c9a4e698" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_722563a9-e38b-4c13-853c-91f46fd37956" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis_8da42729-1562-4ed0-846c-41a9c9a4e698" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_e3ace0a1-64e3-4ca8-a963-f0ef99669b7f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_722563a9-e38b-4c13-853c-91f46fd37956" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_e3ace0a1-64e3-4ca8-a963-f0ef99669b7f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_c44312ca-1974-4eb7-8318-c2a76621d436" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_722563a9-e38b-4c13-853c-91f46fd37956" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_c44312ca-1974-4eb7-8318-c2a76621d436" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_f78350c4-8fca-45b9-8673-a3a87ff93d3e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AvailableForSaleSecuritiesDebtSecurities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_722563a9-e38b-4c13-853c-91f46fd37956" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_f78350c4-8fca-45b9-8673-a3a87ff93d3e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesTable_6b9079e2-2c2c-447e-804f-6714a6c373a1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_722563a9-e38b-4c13-853c-91f46fd37956" xlink:to="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesTable_6b9079e2-2c2c-447e-804f-6714a6c373a1" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_b5151a47-9f8e-4bbe-8075-d402b06e41a9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesTable_6b9079e2-2c2c-447e-804f-6714a6c373a1" xlink:to="loc_us-gaap_FinancialInstrumentAxis_b5151a47-9f8e-4bbe-8075-d402b06e41a9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_b5151a47-9f8e-4bbe-8075-d402b06e41a9_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_b5151a47-9f8e-4bbe-8075-d402b06e41a9" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_b5151a47-9f8e-4bbe-8075-d402b06e41a9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_cce1991a-5020-4d8d-8dc0-e7fb404d3d05" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_b5151a47-9f8e-4bbe-8075-d402b06e41a9" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_cce1991a-5020-4d8d-8dc0-e7fb404d3d05" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CertificatesOfDepositMember_4a5699ae-f1d0-496b-9658-16ee7e5abe0f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CertificatesOfDepositMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_cce1991a-5020-4d8d-8dc0-e7fb404d3d05" xlink:to="loc_us-gaap_CertificatesOfDepositMember_4a5699ae-f1d0-496b-9658-16ee7e5abe0f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetBackedSecuritiesMember_a2621f74-b4c7-4ff8-92cd-ba90b02849c4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AssetBackedSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_cce1991a-5020-4d8d-8dc0-e7fb404d3d05" xlink:to="loc_us-gaap_AssetBackedSecuritiesMember_a2621f74-b4c7-4ff8-92cd-ba90b02849c4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateBondSecuritiesMember_aca8f702-9682-4820-9b4e-d2b88ed45601" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CorporateBondSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_cce1991a-5020-4d8d-8dc0-e7fb404d3d05" xlink:to="loc_us-gaap_CorporateBondSecuritiesMember_aca8f702-9682-4820-9b4e-d2b88ed45601" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USGovernmentAgenciesDebtSecuritiesMember_fe42557b-4e48-4133-afde-09de776e18c9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_USGovernmentAgenciesDebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_cce1991a-5020-4d8d-8dc0-e7fb404d3d05" xlink:to="loc_us-gaap_USGovernmentAgenciesDebtSecuritiesMember_fe42557b-4e48-4133-afde-09de776e18c9" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MunicipalBondsMember_5549e334-1727-423b-8155-dd595fbc9cbd" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_MunicipalBondsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_cce1991a-5020-4d8d-8dc0-e7fb404d3d05" xlink:to="loc_us-gaap_MunicipalBondsMember_5549e334-1727-423b-8155-dd595fbc9cbd" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherDebtSecuritiesMember_810b4451-0210-490c-a45a-9264f4bfecc2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherDebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_cce1991a-5020-4d8d-8dc0-e7fb404d3d05" xlink:to="loc_us-gaap_OtherDebtSecuritiesMember_810b4451-0210-490c-a45a-9264f4bfecc2" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_InvestmentLengthAxis_9ff83403-7ddf-4610-962a-5111842580d4" xlink:href="gntx-20221231.xsd#gntx_InvestmentLengthAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesTable_6b9079e2-2c2c-447e-804f-6714a6c373a1" xlink:to="loc_gntx_InvestmentLengthAxis_9ff83403-7ddf-4610-962a-5111842580d4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_InvestmentLengthDomain_9ff83403-7ddf-4610-962a-5111842580d4_default" xlink:href="gntx-20221231.xsd#gntx_InvestmentLengthDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_gntx_InvestmentLengthAxis_9ff83403-7ddf-4610-962a-5111842580d4" xlink:to="loc_gntx_InvestmentLengthDomain_9ff83403-7ddf-4610-962a-5111842580d4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_InvestmentLengthDomain_ea885a29-94b4-4a85-97a1-c87a9ca0fee6" xlink:href="gntx-20221231.xsd#gntx_InvestmentLengthDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_gntx_InvestmentLengthAxis_9ff83403-7ddf-4610-962a-5111842580d4" xlink:to="loc_gntx_InvestmentLengthDomain_ea885a29-94b4-4a85-97a1-c87a9ca0fee6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermInvestmentsMember_6553ad38-1935-4ceb-9689-54b1bebba1f9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortTermInvestmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_gntx_InvestmentLengthDomain_ea885a29-94b4-4a85-97a1-c87a9ca0fee6" xlink:to="loc_us-gaap_ShortTermInvestmentsMember_6553ad38-1935-4ceb-9689-54b1bebba1f9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLongTermInvestmentsMember_840865a9-c858-480c-8f87-99e288a50f30" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherLongTermInvestmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_gntx_InvestmentLengthDomain_ea885a29-94b4-4a85-97a1-c87a9ca0fee6" xlink:to="loc_us-gaap_OtherLongTermInvestmentsMember_840865a9-c858-480c-8f87-99e288a50f30" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_182c2ea3-3992-4cb5-8287-c9176a38a118" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesTable_6b9079e2-2c2c-447e-804f-6714a6c373a1" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_182c2ea3-3992-4cb5-8287-c9176a38a118" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_182c2ea3-3992-4cb5-8287-c9176a38a118_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_182c2ea3-3992-4cb5-8287-c9176a38a118" xlink:to="loc_us-gaap_EquityComponentDomain_182c2ea3-3992-4cb5-8287-c9176a38a118_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_4bb70e4f-d2e2-4ea7-9645-e08a477a2daf" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_182c2ea3-3992-4cb5-8287-c9176a38a118" xlink:to="loc_us-gaap_EquityComponentDomain_4bb70e4f-d2e2-4ea7-9645-e08a477a2daf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_41146624-2cd5-4c0e-a0ba-b97a1112edc9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_4bb70e4f-d2e2-4ea7-9645-e08a477a2daf" xlink:to="loc_us-gaap_CommonStockMember_41146624-2cd5-4c0e-a0ba-b97a1112edc9" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gentex.com/role/SummaryofSignificantAccountingandReportingPoliciesFixedIncomeSecuritiesContractualMaturityDetails" xlink:type="simple" xlink:href="gntx-20221231.xsd#SummaryofSignificantAccountingandReportingPoliciesFixedIncomeSecuritiesContractualMaturityDetails"/>
  <link:definitionLink xlink:role="http://www.gentex.com/role/SummaryofSignificantAccountingandReportingPoliciesFixedIncomeSecuritiesContractualMaturityDetails" xlink:type="extended" id="i97c7a1a5cf304fab9eacffd7f11b3b83_SummaryofSignificantAccountingandReportingPoliciesFixedIncomeSecuritiesContractualMaturityDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_7f839dab-7f85-48b5-82d2-729bc9eda708" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue_3f922b32-9b0c-4bfb-b6e9-b99a4ec11a09" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_7f839dab-7f85-48b5-82d2-729bc9eda708" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue_3f922b32-9b0c-4bfb-b6e9-b99a4ec11a09" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue_7fc87a0c-93a6-4d05-8ad1-14450d9ea84a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_7f839dab-7f85-48b5-82d2-729bc9eda708" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue_7fc87a0c-93a6-4d05-8ad1-14450d9ea84a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_DebtSecuritiesAvailableForSaleMaturityAllocatedAndSingleMaturityDateAfterFiveYearsFairValue_f378fd3a-81a3-4281-8fe1-b0ebdcd81e51" xlink:href="gntx-20221231.xsd#gntx_DebtSecuritiesAvailableForSaleMaturityAllocatedAndSingleMaturityDateAfterFiveYearsFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_7f839dab-7f85-48b5-82d2-729bc9eda708" xlink:to="loc_gntx_DebtSecuritiesAvailableForSaleMaturityAllocatedAndSingleMaturityDateAfterFiveYearsFairValue_f378fd3a-81a3-4281-8fe1-b0ebdcd81e51" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_f1410278-a37e-4299-af52-bb1abf7886c1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AvailableForSaleSecuritiesDebtSecurities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_7f839dab-7f85-48b5-82d2-729bc9eda708" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_f1410278-a37e-4299-af52-bb1abf7886c1" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesTable_89782459-011f-4c8a-87ea-122c4c4abc18" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_7f839dab-7f85-48b5-82d2-729bc9eda708" xlink:to="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesTable_89782459-011f-4c8a-87ea-122c4c4abc18" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_04166a1f-06b3-432e-805b-ba19104c3f17" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesTable_89782459-011f-4c8a-87ea-122c4c4abc18" xlink:to="loc_us-gaap_FinancialInstrumentAxis_04166a1f-06b3-432e-805b-ba19104c3f17" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_04166a1f-06b3-432e-805b-ba19104c3f17_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_04166a1f-06b3-432e-805b-ba19104c3f17" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_04166a1f-06b3-432e-805b-ba19104c3f17_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_d22a3865-3ff1-4c38-809e-6428724e892f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_04166a1f-06b3-432e-805b-ba19104c3f17" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_d22a3865-3ff1-4c38-809e-6428724e892f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FixedIncomeSecuritiesMember_9a9df5f5-d2b6-42db-bfbe-027a24542375" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FixedIncomeSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_d22a3865-3ff1-4c38-809e-6428724e892f" xlink:to="loc_us-gaap_FixedIncomeSecuritiesMember_9a9df5f5-d2b6-42db-bfbe-027a24542375" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gentex.com/role/DebtandFinancingArrangementsDetails" xlink:type="simple" xlink:href="gntx-20221231.xsd#DebtandFinancingArrangementsDetails"/>
  <link:definitionLink xlink:role="http://www.gentex.com/role/DebtandFinancingArrangementsDetails" xlink:type="extended" id="i8ed6d5c4b31847fdbde35e0dfb27cfdc_DebtandFinancingArrangementsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_769e1a08-864f-4693-ad3d-724f7a724ade" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_d47c8915-37ab-4aaf-a3ed-9302f34f8e49" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_769e1a08-864f-4693-ad3d-724f7a724ade" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_d47c8915-37ab-4aaf-a3ed-9302f34f8e49" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_DebtInstrumentAdditionalBorrowingsAvailableFaceAmount_a656fa4d-400f-4032-9fee-03c3f64b8029" xlink:href="gntx-20221231.xsd#gntx_DebtInstrumentAdditionalBorrowingsAvailableFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_769e1a08-864f-4693-ad3d-724f7a724ade" xlink:to="loc_gntx_DebtInstrumentAdditionalBorrowingsAvailableFaceAmount_a656fa4d-400f-4032-9fee-03c3f64b8029" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt_c7aa2684-c78e-4476-be20-2b12ccd52bb1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_769e1a08-864f-4693-ad3d-724f7a724ade" xlink:to="loc_us-gaap_LongTermDebt_c7aa2684-c78e-4476-be20-2b12ccd52bb1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTerm_a7d6eb4b-70e6-4a68-ac7a-ce787ac44328" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_769e1a08-864f-4693-ad3d-724f7a724ade" xlink:to="loc_us-gaap_DebtInstrumentTerm_a7d6eb4b-70e6-4a68-ac7a-ce787ac44328" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_2f4834ee-0d65-43db-8207-c2c5d6e8077a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_769e1a08-864f-4693-ad3d-724f7a724ade" xlink:to="loc_us-gaap_DebtInstrumentTable_2f4834ee-0d65-43db-8207-c2c5d6e8077a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_682a94a5-d3b7-4c3f-a0ae-1eca311fe812" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_2f4834ee-0d65-43db-8207-c2c5d6e8077a" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_682a94a5-d3b7-4c3f-a0ae-1eca311fe812" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_682a94a5-d3b7-4c3f-a0ae-1eca311fe812_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_682a94a5-d3b7-4c3f-a0ae-1eca311fe812" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_682a94a5-d3b7-4c3f-a0ae-1eca311fe812_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_6e46a807-718c-455d-b8ad-00cc5c42ecdd" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_682a94a5-d3b7-4c3f-a0ae-1eca311fe812" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_6e46a807-718c-455d-b8ad-00cc5c42ecdd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_17a3c4bc-fea5-48c4-a961-4896b6ba5594" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_6e46a807-718c-455d-b8ad-00cc5c42ecdd" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_17a3c4bc-fea5-48c4-a961-4896b6ba5594" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_SwingLoansMember_ecebf5b7-05a6-4de8-96e1-b1d00705d17b" xlink:href="gntx-20221231.xsd#gntx_SwingLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_6e46a807-718c-455d-b8ad-00cc5c42ecdd" xlink:to="loc_gntx_SwingLoansMember_ecebf5b7-05a6-4de8-96e1-b1d00705d17b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LetterOfCreditMember_8f2f27f0-d00d-488a-9c37-d0a2bc30a7be" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LetterOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_6e46a807-718c-455d-b8ad-00cc5c42ecdd" xlink:to="loc_us-gaap_LetterOfCreditMember_8f2f27f0-d00d-488a-9c37-d0a2bc30a7be" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_0d9015ae-9972-4626-aa16-c783336f2941" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SubsequentEventTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_2f4834ee-0d65-43db-8207-c2c5d6e8077a" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_0d9015ae-9972-4626-aa16-c783336f2941" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_0d9015ae-9972-4626-aa16-c783336f2941_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_0d9015ae-9972-4626-aa16-c783336f2941" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_0d9015ae-9972-4626-aa16-c783336f2941_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_7b158dfd-1204-4fa2-8ba4-d1cf045f7731" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_0d9015ae-9972-4626-aa16-c783336f2941" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_7b158dfd-1204-4fa2-8ba4-d1cf045f7731" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventMember_fab75026-d299-422c-87dd-6475ac247313" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SubsequentEventMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_7b158dfd-1204-4fa2-8ba4-d1cf045f7731" xlink:to="loc_us-gaap_SubsequentEventMember_fab75026-d299-422c-87dd-6475ac247313" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gentex.com/role/IncomeTaxesScheduleofDeferredIncomeTaxAssetsandLiabilitiesDetails" xlink:type="simple" xlink:href="gntx-20221231.xsd#IncomeTaxesScheduleofDeferredIncomeTaxAssetsandLiabilitiesDetails"/>
  <link:definitionLink xlink:role="http://www.gentex.com/role/IncomeTaxesScheduleofDeferredIncomeTaxAssetsandLiabilitiesDetails" xlink:type="extended" id="i9e12b767eba14eeeb6442336b98ea761_IncomeTaxesScheduleofDeferredIncomeTaxAssetsandLiabilitiesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxContingencyLineItems_96c3f7f3-0ae6-4c41-96b4-165c2a8620bd" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeTaxContingencyLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComponentsOfDeferredTaxAssetsAbstract_90c8bd5c-96f8-4df1-b289-04b578e6fdf8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ComponentsOfDeferredTaxAssetsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxContingencyLineItems_96c3f7f3-0ae6-4c41-96b4-165c2a8620bd" xlink:to="loc_us-gaap_ComponentsOfDeferredTaxAssetsAbstract_90c8bd5c-96f8-4df1-b289-04b578e6fdf8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccruals_20ca2c0c-6132-40e3-a730-f7931a5eefed" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccruals"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComponentsOfDeferredTaxAssetsAbstract_90c8bd5c-96f8-4df1-b289-04b578e6fdf8" xlink:to="loc_us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccruals_20ca2c0c-6132-40e3-a730-f7931a5eefed" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxAssetsInProcessResearchAndDevelopment_f0319abd-2cf5-41e8-9151-a903e73e2157" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DeferredTaxAssetsInProcessResearchAndDevelopment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComponentsOfDeferredTaxAssetsAbstract_90c8bd5c-96f8-4df1-b289-04b578e6fdf8" xlink:to="loc_us-gaap_DeferredTaxAssetsInProcessResearchAndDevelopment_f0319abd-2cf5-41e8-9151-a903e73e2157" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost_84082967-43af-4b83-9817-4b6a522165ad" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComponentsOfDeferredTaxAssetsAbstract_90c8bd5c-96f8-4df1-b289-04b578e6fdf8" xlink:to="loc_us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost_84082967-43af-4b83-9817-4b6a522165ad" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxAssetsOther_4d66bf61-2ce6-42f0-8d14-d1bb96275824" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DeferredTaxAssetsOther"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComponentsOfDeferredTaxAssetsAbstract_90c8bd5c-96f8-4df1-b289-04b578e6fdf8" xlink:to="loc_us-gaap_DeferredTaxAssetsOther_4d66bf61-2ce6-42f0-8d14-d1bb96275824" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxAssetsNet_0f998e35-dc11-46b4-988a-4dc4b556fd9f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DeferredTaxAssetsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComponentsOfDeferredTaxAssetsAbstract_90c8bd5c-96f8-4df1-b289-04b578e6fdf8" xlink:to="loc_us-gaap_DeferredTaxAssetsNet_0f998e35-dc11-46b4-988a-4dc4b556fd9f" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComponentsOfDeferredTaxLiabilitiesAbstract_08509dd1-7e18-41d9-ac89-fdf5129b2600" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ComponentsOfDeferredTaxLiabilitiesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxContingencyLineItems_96c3f7f3-0ae6-4c41-96b4-165c2a8620bd" xlink:to="loc_us-gaap_ComponentsOfDeferredTaxLiabilitiesAbstract_08509dd1-7e18-41d9-ac89-fdf5129b2600" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_DeferredTaxLiabilitiesDeferredExpenseExcessTaxOverBookDepreciation_609685c6-08b2-4b5a-8132-e5799a1003f8" xlink:href="gntx-20221231.xsd#gntx_DeferredTaxLiabilitiesDeferredExpenseExcessTaxOverBookDepreciation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComponentsOfDeferredTaxLiabilitiesAbstract_08509dd1-7e18-41d9-ac89-fdf5129b2600" xlink:to="loc_gntx_DeferredTaxLiabilitiesDeferredExpenseExcessTaxOverBookDepreciation_609685c6-08b2-4b5a-8132-e5799a1003f8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxLiabilitiesDeferredExpenseCapitalizedPatentCosts_8b1bf1b9-fa26-4ba2-a906-7af3cf0a8d1f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DeferredTaxLiabilitiesDeferredExpenseCapitalizedPatentCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComponentsOfDeferredTaxLiabilitiesAbstract_08509dd1-7e18-41d9-ac89-fdf5129b2600" xlink:to="loc_us-gaap_DeferredTaxLiabilitiesDeferredExpenseCapitalizedPatentCosts_8b1bf1b9-fa26-4ba2-a906-7af3cf0a8d1f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxLiabilitiesGoodwillAndIntangibleAssetsIntangibleAssets_58a0809f-15af-4a4f-8e11-a5d11e6df8df" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DeferredTaxLiabilitiesGoodwillAndIntangibleAssetsIntangibleAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComponentsOfDeferredTaxLiabilitiesAbstract_08509dd1-7e18-41d9-ac89-fdf5129b2600" xlink:to="loc_us-gaap_DeferredTaxLiabilitiesGoodwillAndIntangibleAssetsIntangibleAssets_58a0809f-15af-4a4f-8e11-a5d11e6df8df" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxLiabilitiesOther_08cc0cdc-5965-46e2-9d42-5a49d7e54655" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DeferredTaxLiabilitiesOther"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComponentsOfDeferredTaxLiabilitiesAbstract_08509dd1-7e18-41d9-ac89-fdf5129b2600" xlink:to="loc_us-gaap_DeferredTaxLiabilitiesOther_08cc0cdc-5965-46e2-9d42-5a49d7e54655" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxLiabilities_8158b7c9-e7ee-4889-855c-4d56b6dc70e3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DeferredIncomeTaxLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ComponentsOfDeferredTaxLiabilitiesAbstract_08509dd1-7e18-41d9-ac89-fdf5129b2600" xlink:to="loc_us-gaap_DeferredIncomeTaxLiabilities_8158b7c9-e7ee-4889-855c-4d56b6dc70e3" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxAssetsNet_8bfe3d33-5377-412b-8eb7-4f7ee2f26536" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DeferredIncomeTaxAssetsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxContingencyLineItems_96c3f7f3-0ae6-4c41-96b4-165c2a8620bd" xlink:to="loc_us-gaap_DeferredIncomeTaxAssetsNet_8bfe3d33-5377-412b-8eb7-4f7ee2f26536" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxContingencyTable_a9a23a92-2997-42cc-8557-29c919f60f41" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeTaxContingencyTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_IncomeTaxContingencyLineItems_96c3f7f3-0ae6-4c41-96b4-165c2a8620bd" xlink:to="loc_us-gaap_IncomeTaxContingencyTable_a9a23a92-2997-42cc-8557-29c919f60f41" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_82690761-d31c-4a31-a7d3-00f09b2d7d2f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeTaxContingencyTable_a9a23a92-2997-42cc-8557-29c919f60f41" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_82690761-d31c-4a31-a7d3-00f09b2d7d2f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_82690761-d31c-4a31-a7d3-00f09b2d7d2f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_82690761-d31c-4a31-a7d3-00f09b2d7d2f" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_82690761-d31c-4a31-a7d3-00f09b2d7d2f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_e95324d6-b592-47ba-8acb-d402fc0fca0c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_82690761-d31c-4a31-a7d3-00f09b2d7d2f" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_e95324d6-b592-47ba-8acb-d402fc0fca0c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_PatentAndOtherAssetsNetMember_89850e86-c32b-4284-b57f-3128823c4f28" xlink:href="gntx-20221231.xsd#gntx_PatentAndOtherAssetsNetMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_e95324d6-b592-47ba-8acb-d402fc0fca0c" xlink:to="loc_gntx_PatentAndOtherAssetsNetMember_89850e86-c32b-4284-b57f-3128823c4f28" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gentex.com/role/EmployeeBenefitPlansDetails" xlink:type="simple" xlink:href="gntx-20221231.xsd#EmployeeBenefitPlansDetails"/>
  <link:definitionLink xlink:role="http://www.gentex.com/role/EmployeeBenefitPlansDetails" xlink:type="extended" id="i96313bba626b4c22897671e50da62711_EmployeeBenefitPlansDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredCompensationArrangementWithIndividualPostretirementBenefitsLineItems_034d9f51-3c39-4911-90d0-dd7ee2ddb721" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DeferredCompensationArrangementWithIndividualPostretirementBenefitsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanContributionsByEmployer_4d9afa7f-9279-49ac-8528-d5629cdd5eaa" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanContributionsByEmployer"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DeferredCompensationArrangementWithIndividualPostretirementBenefitsLineItems_034d9f51-3c39-4911-90d0-dd7ee2ddb721" xlink:to="loc_us-gaap_DefinedBenefitPlanContributionsByEmployer_4d9afa7f-9279-49ac-8528-d5629cdd5eaa" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_DeferredCompensationArrangementwithIndividualVestingPercentage_c5f7f025-d3f4-40d4-be2a-7a32a3f880ac" xlink:href="gntx-20221231.xsd#gntx_DeferredCompensationArrangementwithIndividualVestingPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DeferredCompensationArrangementWithIndividualPostretirementBenefitsLineItems_034d9f51-3c39-4911-90d0-dd7ee2ddb721" xlink:to="loc_gntx_DeferredCompensationArrangementwithIndividualVestingPercentage_c5f7f025-d3f4-40d4-be2a-7a32a3f880ac" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredCompensationArrangementWithIndividualRequisiteServicePeriod1_c40aab4b-c4c0-4aa2-8f85-bf7f83f9369d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DeferredCompensationArrangementWithIndividualRequisiteServicePeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DeferredCompensationArrangementWithIndividualPostretirementBenefitsLineItems_034d9f51-3c39-4911-90d0-dd7ee2ddb721" xlink:to="loc_us-gaap_DeferredCompensationArrangementWithIndividualRequisiteServicePeriod1_c40aab4b-c4c0-4aa2-8f85-bf7f83f9369d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredCompensationCashbasedArrangementsLiabilityCurrentAndNoncurrent_b0bd30c2-60cc-4033-bedf-77ea919d0cfd" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DeferredCompensationCashbasedArrangementsLiabilityCurrentAndNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DeferredCompensationArrangementWithIndividualPostretirementBenefitsLineItems_034d9f51-3c39-4911-90d0-dd7ee2ddb721" xlink:to="loc_us-gaap_DeferredCompensationCashbasedArrangementsLiabilityCurrentAndNoncurrent_b0bd30c2-60cc-4033-bedf-77ea919d0cfd" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsHeldInTrust_c42f2def-57c6-47d4-9bd2-de8ab99a3022" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AssetsHeldInTrust"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DeferredCompensationArrangementWithIndividualPostretirementBenefitsLineItems_034d9f51-3c39-4911-90d0-dd7ee2ddb721" xlink:to="loc_us-gaap_AssetsHeldInTrust_c42f2def-57c6-47d4-9bd2-de8ab99a3022" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfDeferredCompensationArrangementWithIndividualPostretirementBenefitsTable_68349127-3449-43ec-a76a-d10db799461b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfDeferredCompensationArrangementWithIndividualPostretirementBenefitsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DeferredCompensationArrangementWithIndividualPostretirementBenefitsLineItems_034d9f51-3c39-4911-90d0-dd7ee2ddb721" xlink:to="loc_us-gaap_ScheduleOfDeferredCompensationArrangementWithIndividualPostretirementBenefitsTable_68349127-3449-43ec-a76a-d10db799461b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VestingAxis_977bb296-ff0d-4cba-a5a5-1ed69de5dfb3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_VestingAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDeferredCompensationArrangementWithIndividualPostretirementBenefitsTable_68349127-3449-43ec-a76a-d10db799461b" xlink:to="loc_us-gaap_VestingAxis_977bb296-ff0d-4cba-a5a5-1ed69de5dfb3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VestingDomain_977bb296-ff0d-4cba-a5a5-1ed69de5dfb3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_VestingDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_VestingAxis_977bb296-ff0d-4cba-a5a5-1ed69de5dfb3" xlink:to="loc_us-gaap_VestingDomain_977bb296-ff0d-4cba-a5a5-1ed69de5dfb3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VestingDomain_af491ec7-6bb1-42e0-89a3-bcf0a11dd759" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_VestingDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_VestingAxis_977bb296-ff0d-4cba-a5a5-1ed69de5dfb3" xlink:to="loc_us-gaap_VestingDomain_af491ec7-6bb1-42e0-89a3-bcf0a11dd759" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_DeferredCompensationArrangementWithIndividualTrancheOneMember_52713219-a5d1-4c97-bbf9-da8ce72cb95f" xlink:href="gntx-20221231.xsd#gntx_DeferredCompensationArrangementWithIndividualTrancheOneMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VestingDomain_af491ec7-6bb1-42e0-89a3-bcf0a11dd759" xlink:to="loc_gntx_DeferredCompensationArrangementWithIndividualTrancheOneMember_52713219-a5d1-4c97-bbf9-da8ce72cb95f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_DeferredCompensationArrangementWithIndividualTrancheTwoMember_9b2287fc-e52b-4c40-8a37-499f089571ea" xlink:href="gntx-20221231.xsd#gntx_DeferredCompensationArrangementWithIndividualTrancheTwoMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VestingDomain_af491ec7-6bb1-42e0-89a3-bcf0a11dd759" xlink:to="loc_gntx_DeferredCompensationArrangementWithIndividualTrancheTwoMember_9b2287fc-e52b-4c40-8a37-499f089571ea" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_daad95e5-d25f-46e1-8a20-ec28bb26437f" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDeferredCompensationArrangementWithIndividualPostretirementBenefitsTable_68349127-3449-43ec-a76a-d10db799461b" xlink:to="loc_srt_RangeAxis_daad95e5-d25f-46e1-8a20-ec28bb26437f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_daad95e5-d25f-46e1-8a20-ec28bb26437f_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_daad95e5-d25f-46e1-8a20-ec28bb26437f" xlink:to="loc_srt_RangeMember_daad95e5-d25f-46e1-8a20-ec28bb26437f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_386d1b32-2e77-42a6-9617-6b1da833b236" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_daad95e5-d25f-46e1-8a20-ec28bb26437f" xlink:to="loc_srt_RangeMember_386d1b32-2e77-42a6-9617-6b1da833b236" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_cbb1cffe-abf4-4219-a157-e090d4f2b1a0" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_386d1b32-2e77-42a6-9617-6b1da833b236" xlink:to="loc_srt_MinimumMember_cbb1cffe-abf4-4219-a157-e090d4f2b1a0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_3fb386f4-5dce-4a18-a637-da5fe9869eb2" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_386d1b32-2e77-42a6-9617-6b1da833b236" xlink:to="loc_srt_MaximumMember_3fb386f4-5dce-4a18-a637-da5fe9869eb2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_21f2e5f1-61ec-4c7d-bbc1-e68aee088fa9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDeferredCompensationArrangementWithIndividualPostretirementBenefitsTable_68349127-3449-43ec-a76a-d10db799461b" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_21f2e5f1-61ec-4c7d-bbc1-e68aee088fa9" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_21f2e5f1-61ec-4c7d-bbc1-e68aee088fa9_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_21f2e5f1-61ec-4c7d-bbc1-e68aee088fa9" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_21f2e5f1-61ec-4c7d-bbc1-e68aee088fa9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_852013e6-bd2a-4a99-a214-5dc7d96d57d4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_21f2e5f1-61ec-4c7d-bbc1-e68aee088fa9" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_852013e6-bd2a-4a99-a214-5dc7d96d57d4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsMember_ae6bdb4a-ca5a-46ec-8e24-7bb7ed741d6a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_852013e6-bd2a-4a99-a214-5dc7d96d57d4" xlink:to="loc_us-gaap_OtherAssetsMember_ae6bdb4a-ca5a-46ec-8e24-7bb7ed741d6a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilitiesMember_f8eb4a23-52c4-479f-bb98-83015ce61ce7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherLiabilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_852013e6-bd2a-4a99-a214-5dc7d96d57d4" xlink:to="loc_us-gaap_OtherLiabilitiesMember_f8eb4a23-52c4-479f-bb98-83015ce61ce7" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gentex.com/role/StockBasedCompensationPlansNarrativeDetails" xlink:type="simple" xlink:href="gntx-20221231.xsd#StockBasedCompensationPlansNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.gentex.com/role/StockBasedCompensationPlansNarrativeDetails" xlink:type="extended" id="i20ea27fe833441b0b11e99ba132dca5a_StockBasedCompensationPlansNarrativeDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_6f6d616d-3a21-4438-848b-1172c7465a13" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_SharebasedCompensationArrangementbySharebasedPaymentAwardNumberofPlans_cc3d87ed-64a8-4c1e-a1d2-a5e6594b0fdd" xlink:href="gntx-20221231.xsd#gntx_SharebasedCompensationArrangementbySharebasedPaymentAwardNumberofPlans"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_6f6d616d-3a21-4438-848b-1172c7465a13" xlink:to="loc_gntx_SharebasedCompensationArrangementbySharebasedPaymentAwardNumberofPlans_cc3d87ed-64a8-4c1e-a1d2-a5e6594b0fdd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_0650b67d-2e7f-4539-8baa-fbf3459171d3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_6f6d616d-3a21-4438-848b-1172c7465a13" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_0650b67d-2e7f-4539-8baa-fbf3459171d3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_SharebasedCompensationArrangementbySharebasedPaymentAwardNumberofSharesIssuedNetOfSharesCanceledOrExpired_37013a17-1031-421b-bdf0-b894172a6b06" xlink:href="gntx-20221231.xsd#gntx_SharebasedCompensationArrangementbySharebasedPaymentAwardNumberofSharesIssuedNetOfSharesCanceledOrExpired"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_6f6d616d-3a21-4438-848b-1172c7465a13" xlink:to="loc_gntx_SharebasedCompensationArrangementbySharebasedPaymentAwardNumberofSharesIssuedNetOfSharesCanceledOrExpired_37013a17-1031-421b-bdf0-b894172a6b06" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrants_76f5c5e1-1b5d-463c-bcac-d8544dcccdab" xlink:href="gntx-20221231.xsd#gntx_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrants"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_6f6d616d-3a21-4438-848b-1172c7465a13" xlink:to="loc_gntx_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrants_76f5c5e1-1b5d-463c-bcac-d8544dcccdab" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_1142a010-c152-42cd-97c9-80faf9c3bb46" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_6f6d616d-3a21-4438-848b-1172c7465a13" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_1142a010-c152-42cd-97c9-80faf9c3bb46" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_43f414d3-f864-45f2-8bf7-b7b511a18e1c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_6f6d616d-3a21-4438-848b-1172c7465a13" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_43f414d3-f864-45f2-8bf7-b7b511a18e1c" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_5997f39d-d3ad-4721-a792-5c75890e59da" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_6f6d616d-3a21-4438-848b-1172c7465a13" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_5997f39d-d3ad-4721-a792-5c75890e59da" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_e796617b-f248-4af1-84e2-4fa42e18004f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_6f6d616d-3a21-4438-848b-1172c7465a13" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_e796617b-f248-4af1-84e2-4fa42e18004f" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_a1b97e6e-239d-4f17-a295-f00051e400ee" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AllocatedShareBasedCompensationExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_6f6d616d-3a21-4438-848b-1172c7465a13" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_a1b97e6e-239d-4f17-a295-f00051e400ee" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_ShareBasedCompensationRestrictedPeriod_fba7613b-f50a-4900-9ff9-caad9093654f" xlink:href="gntx-20221231.xsd#gntx_ShareBasedCompensationRestrictedPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_6f6d616d-3a21-4438-848b-1172c7465a13" xlink:to="loc_gntx_ShareBasedCompensationRestrictedPeriod_fba7613b-f50a-4900-9ff9-caad9093654f" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_bfd7dade-b192-4e73-9034-bdb298611486" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_6f6d616d-3a21-4438-848b-1172c7465a13" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_bfd7dade-b192-4e73-9034-bdb298611486" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardGross_2e6ad802-8bf2-471f-a5f0-998d2ef12fa3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_6f6d616d-3a21-4438-848b-1172c7465a13" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardGross_2e6ad802-8bf2-471f-a5f0-998d2ef12fa3" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredCompensationEquity_4cd60b7d-ddfc-438f-9ba2-f5ad9d460714" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DeferredCompensationEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_6f6d616d-3a21-4438-848b-1172c7465a13" xlink:to="loc_us-gaap_DeferredCompensationEquity_4cd60b7d-ddfc-438f-9ba2-f5ad9d460714" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockExpense_282649f0-3d01-4c81-879c-41c7e332ca21" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RestrictedStockExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_6f6d616d-3a21-4438-848b-1172c7465a13" xlink:to="loc_us-gaap_RestrictedStockExpense_282649f0-3d01-4c81-879c-41c7e332ca21" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardDiscountFromMarketPricePurchaseDate_7c168345-4e20-473c-99ab-f6b95e5dac4e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardDiscountFromMarketPricePurchaseDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_6f6d616d-3a21-4438-848b-1172c7465a13" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardDiscountFromMarketPricePurchaseDate_7c168345-4e20-473c-99ab-f6b95e5dac4e" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_73928fcd-9eba-4586-ab0e-d7e160c3278f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_6f6d616d-3a21-4438-848b-1172c7465a13" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_73928fcd-9eba-4586-ab0e-d7e160c3278f" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameAxis_a3b03f46-abfd-47e9-b9c9-7edd9814617e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PlanNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_73928fcd-9eba-4586-ab0e-d7e160c3278f" xlink:to="loc_us-gaap_PlanNameAxis_a3b03f46-abfd-47e9-b9c9-7edd9814617e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_a3b03f46-abfd-47e9-b9c9-7edd9814617e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PlanNameAxis_a3b03f46-abfd-47e9-b9c9-7edd9814617e" xlink:to="loc_us-gaap_PlanNameDomain_a3b03f46-abfd-47e9-b9c9-7edd9814617e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_d29214cb-d655-4a01-85d1-44698fea67e9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PlanNameAxis_a3b03f46-abfd-47e9-b9c9-7edd9814617e" xlink:to="loc_us-gaap_PlanNameDomain_d29214cb-d655-4a01-85d1-44698fea67e9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_OmnibusIncentivePlanMember_46322dd0-330c-444a-8698-8b4629965a4a" xlink:href="gntx-20221231.xsd#gntx_OmnibusIncentivePlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_d29214cb-d655-4a01-85d1-44698fea67e9" xlink:to="loc_gntx_OmnibusIncentivePlanMember_46322dd0-330c-444a-8698-8b4629965a4a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_EmployeeStockOptionPlanMember_37a99274-90a8-4e79-a807-fa6a73d2f363" xlink:href="gntx-20221231.xsd#gntx_EmployeeStockOptionPlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_d29214cb-d655-4a01-85d1-44698fea67e9" xlink:to="loc_gntx_EmployeeStockOptionPlanMember_37a99274-90a8-4e79-a807-fa6a73d2f363" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_RestrictedStockPlanMember_5288ebad-4a87-4959-ae66-29d77cc07a77" xlink:href="gntx-20221231.xsd#gntx_RestrictedStockPlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_d29214cb-d655-4a01-85d1-44698fea67e9" xlink:to="loc_gntx_RestrictedStockPlanMember_5288ebad-4a87-4959-ae66-29d77cc07a77" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_207f95ec-773f-4949-9b93-590fdf07b9a4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_73928fcd-9eba-4586-ab0e-d7e160c3278f" xlink:to="loc_us-gaap_AwardTypeAxis_207f95ec-773f-4949-9b93-590fdf07b9a4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_207f95ec-773f-4949-9b93-590fdf07b9a4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_207f95ec-773f-4949-9b93-590fdf07b9a4" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_207f95ec-773f-4949-9b93-590fdf07b9a4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_676f9985-e49b-42c0-a741-d33c22231dbd" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_207f95ec-773f-4949-9b93-590fdf07b9a4" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_676f9985-e49b-42c0-a741-d33c22231dbd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockCompensationPlanMember_75fe4f83-f869-4daf-a327-4dc9a14cbd8a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockCompensationPlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_676f9985-e49b-42c0-a741-d33c22231dbd" xlink:to="loc_us-gaap_StockCompensationPlanMember_75fe4f83-f869-4daf-a327-4dc9a14cbd8a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockOptionMember_02981b3c-6aa1-4ee2-93ca-94dc1f0eda0f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EmployeeStockOptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_676f9985-e49b-42c0-a741-d33c22231dbd" xlink:to="loc_us-gaap_EmployeeStockOptionMember_02981b3c-6aa1-4ee2-93ca-94dc1f0eda0f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PerformanceSharesMember_7e1d69b4-ba06-4466-a804-ba3d8692a7d0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PerformanceSharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_676f9985-e49b-42c0-a741-d33c22231dbd" xlink:to="loc_us-gaap_PerformanceSharesMember_7e1d69b4-ba06-4466-a804-ba3d8692a7d0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_f7e895d6-f8e0-40bb-ba40-3ea5dc16bfeb" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_73928fcd-9eba-4586-ab0e-d7e160c3278f" xlink:to="loc_srt_RangeAxis_f7e895d6-f8e0-40bb-ba40-3ea5dc16bfeb" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_f7e895d6-f8e0-40bb-ba40-3ea5dc16bfeb_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_f7e895d6-f8e0-40bb-ba40-3ea5dc16bfeb" xlink:to="loc_srt_RangeMember_f7e895d6-f8e0-40bb-ba40-3ea5dc16bfeb_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_394d7ad4-35ed-48af-9926-44a30a327098" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_f7e895d6-f8e0-40bb-ba40-3ea5dc16bfeb" xlink:to="loc_srt_RangeMember_394d7ad4-35ed-48af-9926-44a30a327098" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_e9e215ad-370b-4eb0-8722-7b0f0cab2c91" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_394d7ad4-35ed-48af-9926-44a30a327098" xlink:to="loc_srt_MinimumMember_e9e215ad-370b-4eb0-8722-7b0f0cab2c91" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_d5d8d0e7-4e56-4e9a-9d83-54e442890374" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_394d7ad4-35ed-48af-9926-44a30a327098" xlink:to="loc_srt_MaximumMember_d5d8d0e7-4e56-4e9a-9d83-54e442890374" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockOwnershipPlanESOPDisclosuresByPlanAxis_6dd74554-51c6-44e6-817a-6659d2e70292" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EmployeeStockOwnershipPlanESOPDisclosuresByPlanAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_73928fcd-9eba-4586-ab0e-d7e160c3278f" xlink:to="loc_us-gaap_EmployeeStockOwnershipPlanESOPDisclosuresByPlanAxis_6dd74554-51c6-44e6-817a-6659d2e70292" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockOwnershipPlanESOPPlanDomain_6dd74554-51c6-44e6-817a-6659d2e70292_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EmployeeStockOwnershipPlanESOPPlanDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_EmployeeStockOwnershipPlanESOPDisclosuresByPlanAxis_6dd74554-51c6-44e6-817a-6659d2e70292" xlink:to="loc_us-gaap_EmployeeStockOwnershipPlanESOPPlanDomain_6dd74554-51c6-44e6-817a-6659d2e70292_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockOwnershipPlanESOPPlanDomain_fa6cee3b-c6cb-40a5-8022-1e8aafe55c76" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EmployeeStockOwnershipPlanESOPPlanDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_EmployeeStockOwnershipPlanESOPDisclosuresByPlanAxis_6dd74554-51c6-44e6-817a-6659d2e70292" xlink:to="loc_us-gaap_EmployeeStockOwnershipPlanESOPPlanDomain_fa6cee3b-c6cb-40a5-8022-1e8aafe55c76" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockMember_97bee5c9-5a78-481c-b880-dff605e19c42" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EmployeeStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EmployeeStockOwnershipPlanESOPPlanDomain_fa6cee3b-c6cb-40a5-8022-1e8aafe55c76" xlink:to="loc_us-gaap_EmployeeStockMember_97bee5c9-5a78-481c-b880-dff605e19c42" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsidiarySaleOfStockAxis_d928c252-8dd8-42b6-b558-cc78d6a6a18f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SubsidiarySaleOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_73928fcd-9eba-4586-ab0e-d7e160c3278f" xlink:to="loc_us-gaap_SubsidiarySaleOfStockAxis_d928c252-8dd8-42b6-b558-cc78d6a6a18f" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleOfStockNameOfTransactionDomain_d928c252-8dd8-42b6-b558-cc78d6a6a18f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SaleOfStockNameOfTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsidiarySaleOfStockAxis_d928c252-8dd8-42b6-b558-cc78d6a6a18f" xlink:to="loc_us-gaap_SaleOfStockNameOfTransactionDomain_d928c252-8dd8-42b6-b558-cc78d6a6a18f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleOfStockNameOfTransactionDomain_5df644c9-f7d9-43cf-89a9-9748ac5d3c1d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SaleOfStockNameOfTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsidiarySaleOfStockAxis_d928c252-8dd8-42b6-b558-cc78d6a6a18f" xlink:to="loc_us-gaap_SaleOfStockNameOfTransactionDomain_5df644c9-f7d9-43cf-89a9-9748ac5d3c1d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockMember_b53138dd-d6e6-4e18-bf9e-269ad4945794" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EmployeeStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SaleOfStockNameOfTransactionDomain_5df644c9-f7d9-43cf-89a9-9748ac5d3c1d" xlink:to="loc_us-gaap_EmployeeStockMember_b53138dd-d6e6-4e18-bf9e-269ad4945794" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gentex.com/role/StockBasedCompensationPlansSummaryofSharesUnder2019OmnibusIncentivePlanDetails" xlink:type="simple" xlink:href="gntx-20221231.xsd#StockBasedCompensationPlansSummaryofSharesUnder2019OmnibusIncentivePlanDetails"/>
  <link:definitionLink xlink:role="http://www.gentex.com/role/StockBasedCompensationPlansSummaryofSharesUnder2019OmnibusIncentivePlanDetails" xlink:type="extended" id="i1f5c73dc78994af5b8dc200174d5b4ce_StockBasedCompensationPlansSummaryofSharesUnder2019OmnibusIncentivePlanDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_597b0712-2ac7-4c35-9d75-98596385000b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_7c75e5fd-f5a5-4116-bb50-0c2be9061492" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_597b0712-2ac7-4c35-9d75-98596385000b" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_7c75e5fd-f5a5-4116-bb50-0c2be9061492" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsGranted_7ca13b1a-87e4-4b4c-b4c6-556b68f4ac49" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsGranted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_597b0712-2ac7-4c35-9d75-98596385000b" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsGranted_7ca13b1a-87e4-4b4c-b4c6-556b68f4ac49" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_ShareBasedCompensationArrangementByShareBasedAwardGrantedInPeriod_9e11c06f-3a5c-417c-90e3-358ad277009d" xlink:href="gntx-20221231.xsd#gntx_ShareBasedCompensationArrangementByShareBasedAwardGrantedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_597b0712-2ac7-4c35-9d75-98596385000b" xlink:to="loc_gntx_ShareBasedCompensationArrangementByShareBasedAwardGrantedInPeriod_9e11c06f-3a5c-417c-90e3-358ad277009d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsConversionRate_11c26760-946a-4a92-896a-69d158e5f238" xlink:href="gntx-20221231.xsd#gntx_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsConversionRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_597b0712-2ac7-4c35-9d75-98596385000b" xlink:to="loc_gntx_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsConversionRate_11c26760-946a-4a92-896a-69d158e5f238" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentConversionRate_807912b4-0587-4e64-855b-9048d7495ed0" xlink:href="gntx-20221231.xsd#gntx_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentConversionRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_597b0712-2ac7-4c35-9d75-98596385000b" xlink:to="loc_gntx_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentConversionRate_807912b4-0587-4e64-855b-9048d7495ed0" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriod_a9c00f92-52be-4134-a86b-ded34cc181f2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_597b0712-2ac7-4c35-9d75-98596385000b" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriod_a9c00f92-52be-4134-a86b-ded34cc181f2" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_665c24e4-4c5e-4098-90aa-4404352ddc69" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_597b0712-2ac7-4c35-9d75-98596385000b" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_665c24e4-4c5e-4098-90aa-4404352ddc69" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_03fb65af-bf60-43ac-abe4-fb7fb31165ed" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_665c24e4-4c5e-4098-90aa-4404352ddc69" xlink:to="loc_us-gaap_AwardTypeAxis_03fb65af-bf60-43ac-abe4-fb7fb31165ed" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_03fb65af-bf60-43ac-abe4-fb7fb31165ed_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_03fb65af-bf60-43ac-abe4-fb7fb31165ed" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_03fb65af-bf60-43ac-abe4-fb7fb31165ed_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_004fa8e1-3c1f-4ec1-8862-942a46aebea6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_03fb65af-bf60-43ac-abe4-fb7fb31165ed" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_004fa8e1-3c1f-4ec1-8862-942a46aebea6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_NonQualifiedStockOptionMember_b011e828-7e94-4a6f-a67f-056aab61fdec" xlink:href="gntx-20221231.xsd#gntx_NonQualifiedStockOptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_004fa8e1-3c1f-4ec1-8862-942a46aebea6" xlink:to="loc_gntx_NonQualifiedStockOptionMember_b011e828-7e94-4a6f-a67f-056aab61fdec" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockMember_5f0d1872-029c-4974-95d1-4ed08598aa29" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RestrictedStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_004fa8e1-3c1f-4ec1-8862-942a46aebea6" xlink:to="loc_us-gaap_RestrictedStockMember_5f0d1872-029c-4974-95d1-4ed08598aa29" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PerformanceSharesMember_39b623f7-81eb-451f-a073-559c9c87d40c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PerformanceSharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_004fa8e1-3c1f-4ec1-8862-942a46aebea6" xlink:to="loc_us-gaap_PerformanceSharesMember_39b623f7-81eb-451f-a073-559c9c87d40c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameAxis_07c4c358-f1de-4e26-b398-6e3bf2cb54fa" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PlanNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_665c24e4-4c5e-4098-90aa-4404352ddc69" xlink:to="loc_us-gaap_PlanNameAxis_07c4c358-f1de-4e26-b398-6e3bf2cb54fa" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_07c4c358-f1de-4e26-b398-6e3bf2cb54fa_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PlanNameAxis_07c4c358-f1de-4e26-b398-6e3bf2cb54fa" xlink:to="loc_us-gaap_PlanNameDomain_07c4c358-f1de-4e26-b398-6e3bf2cb54fa_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_2600e290-893e-4c19-bb7e-5c77a0ff3ec0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PlanNameAxis_07c4c358-f1de-4e26-b398-6e3bf2cb54fa" xlink:to="loc_us-gaap_PlanNameDomain_2600e290-893e-4c19-bb7e-5c77a0ff3ec0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_OmnibusIncentivePlanMember_e46ba091-4985-4851-b688-0c4bc726b6de" xlink:href="gntx-20221231.xsd#gntx_OmnibusIncentivePlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_2600e290-893e-4c19-bb7e-5c77a0ff3ec0" xlink:to="loc_gntx_OmnibusIncentivePlanMember_e46ba091-4985-4851-b688-0c4bc726b6de" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gentex.com/role/StockBasedCompensationPlansVestedRestrictedStocksDetails" xlink:type="simple" xlink:href="gntx-20221231.xsd#StockBasedCompensationPlansVestedRestrictedStocksDetails"/>
  <link:definitionLink xlink:role="http://www.gentex.com/role/StockBasedCompensationPlansVestedRestrictedStocksDetails" xlink:type="extended" id="i445eade182444e97af5a0e7c1d77cfdb_StockBasedCompensationPlansVestedRestrictedStocksDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5dd8c828-b44f-4b8a-86a5-0b865f60f54b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsGranted_f0bcc848-16bf-4e72-90cb-f9b661a5510f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsGranted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5dd8c828-b44f-4b8a-86a5-0b865f60f54b" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsGranted_f0bcc848-16bf-4e72-90cb-f9b661a5510f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice_8fbabe68-b03e-43f7-a0cb-1a9daf767913" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5dd8c828-b44f-4b8a-86a5-0b865f60f54b" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice_8fbabe68-b03e-43f7-a0cb-1a9daf767913" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_d91e2971-8043-4778-9774-4e9f361aea20" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5dd8c828-b44f-4b8a-86a5-0b865f60f54b" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_d91e2971-8043-4778-9774-4e9f361aea20" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_63fa7dd8-24f6-44a7-8772-f6e73a892ac2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_d91e2971-8043-4778-9774-4e9f361aea20" xlink:to="loc_us-gaap_AwardTypeAxis_63fa7dd8-24f6-44a7-8772-f6e73a892ac2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_63fa7dd8-24f6-44a7-8772-f6e73a892ac2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_63fa7dd8-24f6-44a7-8772-f6e73a892ac2" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_63fa7dd8-24f6-44a7-8772-f6e73a892ac2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_ca85e0fb-888f-4ad9-aef7-50964e1e4a0b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_63fa7dd8-24f6-44a7-8772-f6e73a892ac2" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_ca85e0fb-888f-4ad9-aef7-50964e1e4a0b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockMember_b6977f25-a387-4aaf-b63b-89098f3a63b1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RestrictedStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_ca85e0fb-888f-4ad9-aef7-50964e1e4a0b" xlink:to="loc_us-gaap_RestrictedStockMember_b6977f25-a387-4aaf-b63b-89098f3a63b1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VestingAxis_49e6cf3e-9352-435b-98e6-60b8b520ef2e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_VestingAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_d91e2971-8043-4778-9774-4e9f361aea20" xlink:to="loc_us-gaap_VestingAxis_49e6cf3e-9352-435b-98e6-60b8b520ef2e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VestingDomain_49e6cf3e-9352-435b-98e6-60b8b520ef2e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_VestingDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_VestingAxis_49e6cf3e-9352-435b-98e6-60b8b520ef2e" xlink:to="loc_us-gaap_VestingDomain_49e6cf3e-9352-435b-98e6-60b8b520ef2e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VestingDomain_d4cc4c82-96a3-40be-a9c3-274db7ea7b4a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_VestingDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_VestingAxis_49e6cf3e-9352-435b-98e6-60b8b520ef2e" xlink:to="loc_us-gaap_VestingDomain_d4cc4c82-96a3-40be-a9c3-274db7ea7b4a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_A1YearMember_838ca770-af9e-45e9-9a38-e9eb4d369db3" xlink:href="gntx-20221231.xsd#gntx_A1YearMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VestingDomain_d4cc4c82-96a3-40be-a9c3-274db7ea7b4a" xlink:to="loc_gntx_A1YearMember_838ca770-af9e-45e9-9a38-e9eb4d369db3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_TwoYearMember_9e503b19-5245-4a49-a0cf-d0b616745576" xlink:href="gntx-20221231.xsd#gntx_TwoYearMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VestingDomain_d4cc4c82-96a3-40be-a9c3-274db7ea7b4a" xlink:to="loc_gntx_TwoYearMember_9e503b19-5245-4a49-a0cf-d0b616745576" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_ThreeYearsMember_4dd28af5-44ee-4a82-895b-fcaa41d27956" xlink:href="gntx-20221231.xsd#gntx_ThreeYearsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VestingDomain_d4cc4c82-96a3-40be-a9c3-274db7ea7b4a" xlink:to="loc_gntx_ThreeYearsMember_4dd28af5-44ee-4a82-895b-fcaa41d27956" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_FourYearMember_a4fd2945-91bd-463b-9c83-8dbfa8842367" xlink:href="gntx-20221231.xsd#gntx_FourYearMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VestingDomain_d4cc4c82-96a3-40be-a9c3-274db7ea7b4a" xlink:to="loc_gntx_FourYearMember_a4fd2945-91bd-463b-9c83-8dbfa8842367" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_FiveYearsMember_33785cf1-0dfa-41f3-aeae-6cc30a3cba1d" xlink:href="gntx-20221231.xsd#gntx_FiveYearsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VestingDomain_d4cc4c82-96a3-40be-a9c3-274db7ea7b4a" xlink:to="loc_gntx_FiveYearsMember_33785cf1-0dfa-41f3-aeae-6cc30a3cba1d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_cb3ab78e-17ec-4be4-98b7-091cdc91af6c" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_d91e2971-8043-4778-9774-4e9f361aea20" xlink:to="loc_srt_RangeAxis_cb3ab78e-17ec-4be4-98b7-091cdc91af6c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_cb3ab78e-17ec-4be4-98b7-091cdc91af6c_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_cb3ab78e-17ec-4be4-98b7-091cdc91af6c" xlink:to="loc_srt_RangeMember_cb3ab78e-17ec-4be4-98b7-091cdc91af6c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_3e351595-5c7c-4405-b456-5bc71b385256" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_cb3ab78e-17ec-4be4-98b7-091cdc91af6c" xlink:to="loc_srt_RangeMember_3e351595-5c7c-4405-b456-5bc71b385256" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_c438f1f0-ebb8-49a4-ad85-df3315a6dbaa" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_3e351595-5c7c-4405-b456-5bc71b385256" xlink:to="loc_srt_MinimumMember_c438f1f0-ebb8-49a4-ad85-df3315a6dbaa" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_06a76de4-36e7-49e2-86e2-e5d636937574" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_3e351595-5c7c-4405-b456-5bc71b385256" xlink:to="loc_srt_MaximumMember_06a76de4-36e7-49e2-86e2-e5d636937574" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gentex.com/role/StockBasedCompensationPlansEmployeeStockPurchasePlanDetails" xlink:type="simple" xlink:href="gntx-20221231.xsd#StockBasedCompensationPlansEmployeeStockPurchasePlanDetails"/>
  <link:definitionLink xlink:role="http://www.gentex.com/role/StockBasedCompensationPlansEmployeeStockPurchasePlanDetails" xlink:type="extended" id="i3df90b1a853a4b2eb28c265c6d699780_StockBasedCompensationPlansEmployeeStockPurchasePlanDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_ca3c197f-3683-44ec-9ad9-7c8d714e3794" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_55a296f3-d77b-4795-a7cf-396bddba8a8b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_ca3c197f-3683-44ec-9ad9-7c8d714e3794" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_55a296f3-d77b-4795-a7cf-396bddba8a8b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_289b3038-d64c-4612-90bf-ef4ba95ae9c1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_ca3c197f-3683-44ec-9ad9-7c8d714e3794" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_289b3038-d64c-4612-90bf-ef4ba95ae9c1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_e5a3aa56-0d13-4adf-8a75-1a9531db7126" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_ca3c197f-3683-44ec-9ad9-7c8d714e3794" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_e5a3aa56-0d13-4adf-8a75-1a9531db7126" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockOwnershipPlanESOPDisclosuresByPlanAxis_bcb39272-409e-4660-8373-c3d2b9f31847" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EmployeeStockOwnershipPlanESOPDisclosuresByPlanAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_e5a3aa56-0d13-4adf-8a75-1a9531db7126" xlink:to="loc_us-gaap_EmployeeStockOwnershipPlanESOPDisclosuresByPlanAxis_bcb39272-409e-4660-8373-c3d2b9f31847" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockOwnershipPlanESOPPlanDomain_bcb39272-409e-4660-8373-c3d2b9f31847_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EmployeeStockOwnershipPlanESOPPlanDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_EmployeeStockOwnershipPlanESOPDisclosuresByPlanAxis_bcb39272-409e-4660-8373-c3d2b9f31847" xlink:to="loc_us-gaap_EmployeeStockOwnershipPlanESOPPlanDomain_bcb39272-409e-4660-8373-c3d2b9f31847_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockOwnershipPlanESOPPlanDomain_9f84ff11-2cf5-4e42-bcbf-ffedff09d5e5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EmployeeStockOwnershipPlanESOPPlanDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_EmployeeStockOwnershipPlanESOPDisclosuresByPlanAxis_bcb39272-409e-4660-8373-c3d2b9f31847" xlink:to="loc_us-gaap_EmployeeStockOwnershipPlanESOPPlanDomain_9f84ff11-2cf5-4e42-bcbf-ffedff09d5e5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_A2022EmployeeStockPurchasePlanMember_4dd3ff21-cef1-417b-952f-bba08fa36153" xlink:href="gntx-20221231.xsd#gntx_A2022EmployeeStockPurchasePlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EmployeeStockOwnershipPlanESOPPlanDomain_9f84ff11-2cf5-4e42-bcbf-ffedff09d5e5" xlink:to="loc_gntx_A2022EmployeeStockPurchasePlanMember_4dd3ff21-cef1-417b-952f-bba08fa36153" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_PriorEmployeeStockPurchasePlanMember_6734d1c7-6a47-4608-8dc6-9ff578f867e0" xlink:href="gntx-20221231.xsd#gntx_PriorEmployeeStockPurchasePlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EmployeeStockOwnershipPlanESOPPlanDomain_9f84ff11-2cf5-4e42-bcbf-ffedff09d5e5" xlink:to="loc_gntx_PriorEmployeeStockPurchasePlanMember_6734d1c7-6a47-4608-8dc6-9ff578f867e0" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gentex.com/role/SegmentReportingScheduleofAutomotiveandOtherSegmentReportingDetails" xlink:type="simple" xlink:href="gntx-20221231.xsd#SegmentReportingScheduleofAutomotiveandOtherSegmentReportingDetails"/>
  <link:definitionLink xlink:role="http://www.gentex.com/role/SegmentReportingScheduleofAutomotiveandOtherSegmentReportingDetails" xlink:type="extended" id="i411c0bbb0449440dbb3f14797968d86b_SegmentReportingScheduleofAutomotiveandOtherSegmentReportingDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_3910a1a7-10d3-440d-abbf-dbf9efc415f5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentReportingInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_8014a43d-dbc5-47ab-ab2c-7fe0d5e79f9b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_3910a1a7-10d3-440d-abbf-dbf9efc415f5" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_8014a43d-dbc5-47ab-ab2c-7fe0d5e79f9b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingIncomeLoss_470ce3ce-7620-4290-8d37-81d5ec6960f2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_3910a1a7-10d3-440d-abbf-dbf9efc415f5" xlink:to="loc_us-gaap_OperatingIncomeLoss_470ce3ce-7620-4290-8d37-81d5ec6960f2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Assets_670a0663-4b70-4fbd-9e7b-34b81e1dd168" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_Assets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_3910a1a7-10d3-440d-abbf-dbf9efc415f5" xlink:to="loc_us-gaap_Assets_670a0663-4b70-4fbd-9e7b-34b81e1dd168" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepreciationDepletionAndAmortization_519eef08-9b89-4cde-83df-3c0ff896938b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DepreciationDepletionAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_3910a1a7-10d3-440d-abbf-dbf9efc415f5" xlink:to="loc_us-gaap_DepreciationDepletionAndAmortization_519eef08-9b89-4cde-83df-3c0ff896938b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireProductiveAssets_c1a53d0f-f8c4-4d35-bba2-27b0291714d3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PaymentsToAcquireProductiveAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_3910a1a7-10d3-440d-abbf-dbf9efc415f5" xlink:to="loc_us-gaap_PaymentsToAcquireProductiveAssets_c1a53d0f-f8c4-4d35-bba2-27b0291714d3" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_f6738d73-c115-4e6a-b428-ff02f0df2acb" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_3910a1a7-10d3-440d-abbf-dbf9efc415f5" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_f6738d73-c115-4e6a-b428-ff02f0df2acb" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis_2285299e-562f-49e4-81af-7fbfcb31017c" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_StatementGeographicalAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_f6738d73-c115-4e6a-b428-ff02f0df2acb" xlink:to="loc_srt_StatementGeographicalAxis_2285299e-562f-49e4-81af-7fbfcb31017c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_2285299e-562f-49e4-81af-7fbfcb31017c_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_2285299e-562f-49e4-81af-7fbfcb31017c" xlink:to="loc_srt_SegmentGeographicalDomain_2285299e-562f-49e4-81af-7fbfcb31017c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_bb912c4d-ffb9-4c3f-9196-62e7c0c27ea2" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_2285299e-562f-49e4-81af-7fbfcb31017c" xlink:to="loc_srt_SegmentGeographicalDomain_bb912c4d-ffb9-4c3f-9196-62e7c0c27ea2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_US_e8559f85-8e20-44df-bcd7-ffd9ca1d8176" xlink:href="https://xbrl.sec.gov/country/2022/country-2022.xsd#country_US"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_bb912c4d-ffb9-4c3f-9196-62e7c0c27ea2" xlink:to="loc_country_US_e8559f85-8e20-44df-bcd7-ffd9ca1d8176" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_DE_d047cbb5-bdca-4b4a-9356-056efed41130" xlink:href="https://xbrl.sec.gov/country/2022/country-2022.xsd#country_DE"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_bb912c4d-ffb9-4c3f-9196-62e7c0c27ea2" xlink:to="loc_country_DE_d047cbb5-bdca-4b4a-9356-056efed41130" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_JP_925611d2-3cc8-477f-9cc1-af4f7e4cb93d" xlink:href="https://xbrl.sec.gov/country/2022/country-2022.xsd#country_JP"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_bb912c4d-ffb9-4c3f-9196-62e7c0c27ea2" xlink:to="loc_country_JP_925611d2-3cc8-477f-9cc1-af4f7e4cb93d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_MX_10878219-8521-49db-9544-acede4856ffa" xlink:href="https://xbrl.sec.gov/country/2022/country-2022.xsd#country_MX"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_bb912c4d-ffb9-4c3f-9196-62e7c0c27ea2" xlink:to="loc_country_MX_10878219-8521-49db-9544-acede4856ffa" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_OtherCountriesMember_db9a3c28-656a-4486-bda8-e3f035008fad" xlink:href="gntx-20221231.xsd#gntx_OtherCountriesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_bb912c4d-ffb9-4c3f-9196-62e7c0c27ea2" xlink:to="loc_gntx_OtherCountriesMember_db9a3c28-656a-4486-bda8-e3f035008fad" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_0e520851-6944-42c1-b617-01b30b20c85d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_f6738d73-c115-4e6a-b428-ff02f0df2acb" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_0e520851-6944-42c1-b617-01b30b20c85d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_0e520851-6944-42c1-b617-01b30b20c85d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_0e520851-6944-42c1-b617-01b30b20c85d" xlink:to="loc_us-gaap_SegmentDomain_0e520851-6944-42c1-b617-01b30b20c85d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_40050380-b0d3-4732-94bc-c4511d0ed65d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_0e520851-6944-42c1-b617-01b30b20c85d" xlink:to="loc_us-gaap_SegmentDomain_40050380-b0d3-4732-94bc-c4511d0ed65d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_AutomotiveProductsSegmentMember_a21233b9-9bfb-43a8-901b-c68a5c024b37" xlink:href="gntx-20221231.xsd#gntx_AutomotiveProductsSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_40050380-b0d3-4732-94bc-c4511d0ed65d" xlink:to="loc_gntx_AutomotiveProductsSegmentMember_a21233b9-9bfb-43a8-901b-c68a5c024b37" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllOtherSegmentsMember_10ef335c-561c-48b0-9758-d7ea1cf43b9e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AllOtherSegmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_40050380-b0d3-4732-94bc-c4511d0ed65d" xlink:to="loc_us-gaap_AllOtherSegmentsMember_10ef335c-561c-48b0-9758-d7ea1cf43b9e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsAxis_b7843735-7a62-4d2a-a99a-20ead512fb14" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ConsolidationItemsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_f6738d73-c115-4e6a-b428-ff02f0df2acb" xlink:to="loc_srt_ConsolidationItemsAxis_b7843735-7a62-4d2a-a99a-20ead512fb14" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_b7843735-7a62-4d2a-a99a-20ead512fb14_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_b7843735-7a62-4d2a-a99a-20ead512fb14" xlink:to="loc_srt_ConsolidationItemsDomain_b7843735-7a62-4d2a-a99a-20ead512fb14_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_c1c405d7-d6c6-4fec-b99b-6989be9e3319" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_b7843735-7a62-4d2a-a99a-20ead512fb14" xlink:to="loc_srt_ConsolidationItemsDomain_c1c405d7-d6c6-4fec-b99b-6989be9e3319" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingSegmentsMember_6a351f4f-65ee-4f5d-8ddc-16cc3011d117" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingSegmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_c1c405d7-d6c6-4fec-b99b-6989be9e3319" xlink:to="loc_us-gaap_OperatingSegmentsMember_6a351f4f-65ee-4f5d-8ddc-16cc3011d117" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateNonSegmentMember_65d62e31-33b9-41f1-99b5-62305b225eb8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CorporateNonSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_c1c405d7-d6c6-4fec-b99b-6989be9e3319" xlink:to="loc_us-gaap_CorporateNonSegmentMember_65d62e31-33b9-41f1-99b5-62305b225eb8" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gentex.com/role/SegmentReportingScheduleofMajorProductLineRevenuesDetails" xlink:type="simple" xlink:href="gntx-20221231.xsd#SegmentReportingScheduleofMajorProductLineRevenuesDetails"/>
  <link:definitionLink xlink:role="http://www.gentex.com/role/SegmentReportingScheduleofMajorProductLineRevenuesDetails" xlink:type="extended" id="i13002c8671fe4f49a42f321929659d46_SegmentReportingScheduleofMajorProductLineRevenuesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EntityWideInformationRevenueFromExternalCustomerLineItems_29b865f4-3058-4088-9cfc-ca1282d1990d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EntityWideInformationRevenueFromExternalCustomerLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_7b21456e-494f-44cb-bf12-a1f5290e1c4f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EntityWideInformationRevenueFromExternalCustomerLineItems_29b865f4-3058-4088-9cfc-ca1282d1990d" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_7b21456e-494f-44cb-bf12-a1f5290e1c4f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTable_91f59b63-f59b-4f84-bdb5-6a38909726e3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_EntityWideInformationRevenueFromExternalCustomerLineItems_29b865f4-3058-4088-9cfc-ca1282d1990d" xlink:to="loc_us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTable_91f59b63-f59b-4f84-bdb5-6a38909726e3" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_1004a1e2-fedb-4afe-a881-ae9382f078b9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTable_91f59b63-f59b-4f84-bdb5-6a38909726e3" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_1004a1e2-fedb-4afe-a881-ae9382f078b9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_1004a1e2-fedb-4afe-a881-ae9382f078b9_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_1004a1e2-fedb-4afe-a881-ae9382f078b9" xlink:to="loc_us-gaap_SegmentDomain_1004a1e2-fedb-4afe-a881-ae9382f078b9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_8d986e84-7b51-4a1b-999f-6c362f15f6d6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_1004a1e2-fedb-4afe-a881-ae9382f078b9" xlink:to="loc_us-gaap_SegmentDomain_8d986e84-7b51-4a1b-999f-6c362f15f6d6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_AutomotiveProductsSegmentMember_62e18e0b-8e1d-4127-bc58-0467cbfbdf9a" xlink:href="gntx-20221231.xsd#gntx_AutomotiveProductsSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_8d986e84-7b51-4a1b-999f-6c362f15f6d6" xlink:to="loc_gntx_AutomotiveProductsSegmentMember_62e18e0b-8e1d-4127-bc58-0467cbfbdf9a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllOtherSegmentsMember_b72a286a-2806-4c93-aea7-4b7c9b9e8361" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AllOtherSegmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_8d986e84-7b51-4a1b-999f-6c362f15f6d6" xlink:to="loc_us-gaap_AllOtherSegmentsMember_b72a286a-2806-4c93-aea7-4b7c9b9e8361" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_278d3d80-57ff-4fa6-ac14-cc298af15660" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTable_91f59b63-f59b-4f84-bdb5-6a38909726e3" xlink:to="loc_srt_ProductOrServiceAxis_278d3d80-57ff-4fa6-ac14-cc298af15660" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_278d3d80-57ff-4fa6-ac14-cc298af15660_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_278d3d80-57ff-4fa6-ac14-cc298af15660" xlink:to="loc_srt_ProductsAndServicesDomain_278d3d80-57ff-4fa6-ac14-cc298af15660_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_8b163231-fd25-4bac-a6c7-4398321cc3f3" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_278d3d80-57ff-4fa6-ac14-cc298af15660" xlink:to="loc_srt_ProductsAndServicesDomain_8b163231-fd25-4bac-a6c7-4398321cc3f3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_AutomotiveMirrorsMember_1965159e-0f4f-4410-8dac-6d904175b65e" xlink:href="gntx-20221231.xsd#gntx_AutomotiveMirrorsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_8b163231-fd25-4bac-a6c7-4398321cc3f3" xlink:to="loc_gntx_AutomotiveMirrorsMember_1965159e-0f4f-4410-8dac-6d904175b65e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_HomeLinkModulesMember_6fc830b7-039e-4ed0-a211-6dfb90e84a74" xlink:href="gntx-20221231.xsd#gntx_HomeLinkModulesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_8b163231-fd25-4bac-a6c7-4398321cc3f3" xlink:to="loc_gntx_HomeLinkModulesMember_6fc830b7-039e-4ed0-a211-6dfb90e84a74" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_OtherProductsMember_4e527ab3-d079-41bd-94c5-53879aa60411" xlink:href="gntx-20221231.xsd#gntx_OtherProductsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_8b163231-fd25-4bac-a6c7-4398321cc3f3" xlink:to="loc_gntx_OtherProductsMember_4e527ab3-d079-41bd-94c5-53879aa60411" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gentex.com/role/SegmentReportingScheduleofAutomotiveCustomersIndividuallyAccountedfor10orMoreofNetSalesDetails" xlink:type="simple" xlink:href="gntx-20221231.xsd#SegmentReportingScheduleofAutomotiveCustomersIndividuallyAccountedfor10orMoreofNetSalesDetails"/>
  <link:definitionLink xlink:role="http://www.gentex.com/role/SegmentReportingScheduleofAutomotiveCustomersIndividuallyAccountedfor10orMoreofNetSalesDetails" xlink:type="extended" id="i666f7c47a6d64b9ab40c7425d20bbfc1_SegmentReportingScheduleofAutomotiveCustomersIndividuallyAccountedfor10orMoreofNetSalesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EntityWideRevenueMajorCustomerLineItems_18cabbda-0bf2-4b9f-9e5f-434798767340" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EntityWideRevenueMajorCustomerLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_PercentageNetSalesInvoicedAndPaidInForeignCurrencies_a1e1b1a7-3761-43d1-9246-830dd8febc7a" xlink:href="gntx-20221231.xsd#gntx_PercentageNetSalesInvoicedAndPaidInForeignCurrencies"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EntityWideRevenueMajorCustomerLineItems_18cabbda-0bf2-4b9f-9e5f-434798767340" xlink:to="loc_gntx_PercentageNetSalesInvoicedAndPaidInForeignCurrencies_a1e1b1a7-3761-43d1-9246-830dd8febc7a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_NumberOfCustomersWhichIndividuallyAccountedFor10PercentOrMoreOfNetSales_398ad547-3d55-4438-b613-1ff5cf997df8" xlink:href="gntx-20221231.xsd#gntx_NumberOfCustomersWhichIndividuallyAccountedFor10PercentOrMoreOfNetSales"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EntityWideRevenueMajorCustomerLineItems_18cabbda-0bf2-4b9f-9e5f-434798767340" xlink:to="loc_gntx_NumberOfCustomersWhichIndividuallyAccountedFor10PercentOrMoreOfNetSales_398ad547-3d55-4438-b613-1ff5cf997df8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskPercentage1_aa71649f-4edf-41dd-b8de-368385693995" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ConcentrationRiskPercentage1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EntityWideRevenueMajorCustomerLineItems_18cabbda-0bf2-4b9f-9e5f-434798767340" xlink:to="loc_us-gaap_ConcentrationRiskPercentage1_aa71649f-4edf-41dd-b8de-368385693995" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEntityWideRevenueByMajorCustomersByReportingSegmentsTable_bdbd2ad2-7a37-449b-90ce-d82e3c000d73" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfEntityWideRevenueByMajorCustomersByReportingSegmentsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_EntityWideRevenueMajorCustomerLineItems_18cabbda-0bf2-4b9f-9e5f-434798767340" xlink:to="loc_us-gaap_ScheduleOfEntityWideRevenueByMajorCustomersByReportingSegmentsTable_bdbd2ad2-7a37-449b-90ce-d82e3c000d73" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis_1006eefd-8ffc-4544-8419-874d7052bbb5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ConcentrationRiskByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEntityWideRevenueByMajorCustomersByReportingSegmentsTable_bdbd2ad2-7a37-449b-90ce-d82e3c000d73" xlink:to="loc_us-gaap_ConcentrationRiskByTypeAxis_1006eefd-8ffc-4544-8419-874d7052bbb5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_1006eefd-8ffc-4544-8419-874d7052bbb5_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_1006eefd-8ffc-4544-8419-874d7052bbb5" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_1006eefd-8ffc-4544-8419-874d7052bbb5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_880a8662-a0b4-4cd8-8a75-0bc959219bb2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_1006eefd-8ffc-4544-8419-874d7052bbb5" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_880a8662-a0b4-4cd8-8a75-0bc959219bb2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerConcentrationRiskMember_7a6c6a16-319e-406c-8a6b-ed5e7929365e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CustomerConcentrationRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_880a8662-a0b4-4cd8-8a75-0bc959219bb2" xlink:to="loc_us-gaap_CustomerConcentrationRiskMember_7a6c6a16-319e-406c-8a6b-ed5e7929365e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MajorCustomersAxis_829001e2-2974-4021-9ef6-b08cff0f89cd" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MajorCustomersAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEntityWideRevenueByMajorCustomersByReportingSegmentsTable_bdbd2ad2-7a37-449b-90ce-d82e3c000d73" xlink:to="loc_srt_MajorCustomersAxis_829001e2-2974-4021-9ef6-b08cff0f89cd" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_829001e2-2974-4021-9ef6-b08cff0f89cd_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_MajorCustomersAxis_829001e2-2974-4021-9ef6-b08cff0f89cd" xlink:to="loc_srt_NameOfMajorCustomerDomain_829001e2-2974-4021-9ef6-b08cff0f89cd_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_3cd0e869-7990-41a6-ae6c-6251ef1ae23a" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_MajorCustomersAxis_829001e2-2974-4021-9ef6-b08cff0f89cd" xlink:to="loc_srt_NameOfMajorCustomerDomain_3cd0e869-7990-41a6-ae6c-6251ef1ae23a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_ToyotaMotorCompanyMember_711a1064-88f1-4885-bf11-eb6d74b4527b" xlink:href="gntx-20221231.xsd#gntx_ToyotaMotorCompanyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_3cd0e869-7990-41a6-ae6c-6251ef1ae23a" xlink:to="loc_gntx_ToyotaMotorCompanyMember_711a1064-88f1-4885-bf11-eb6d74b4527b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_VolkswagenGroupMember_a6d43c52-ae20-4bcb-a112-21eb0e997b5f" xlink:href="gntx-20221231.xsd#gntx_VolkswagenGroupMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_3cd0e869-7990-41a6-ae6c-6251ef1ae23a" xlink:to="loc_gntx_VolkswagenGroupMember_a6d43c52-ae20-4bcb-a112-21eb0e997b5f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_GeneralMotorsCompanyMember_7a84f90c-ed2c-47ea-b36e-a7ab3cc7550f" xlink:href="gntx-20221231.xsd#gntx_GeneralMotorsCompanyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_3cd0e869-7990-41a6-ae6c-6251ef1ae23a" xlink:to="loc_gntx_GeneralMotorsCompanyMember_7a84f90c-ed2c-47ea-b36e-a7ab3cc7550f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_2797482f-8d44-4b74-9574-200c02fcfac7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEntityWideRevenueByMajorCustomersByReportingSegmentsTable_bdbd2ad2-7a37-449b-90ce-d82e3c000d73" xlink:to="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_2797482f-8d44-4b74-9574-200c02fcfac7" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_2797482f-8d44-4b74-9574-200c02fcfac7_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_2797482f-8d44-4b74-9574-200c02fcfac7" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_2797482f-8d44-4b74-9574-200c02fcfac7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_c33567b2-79d3-4658-b612-cf45976d7773" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_2797482f-8d44-4b74-9574-200c02fcfac7" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_c33567b2-79d3-4658-b612-cf45976d7773" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesRevenueNetMember_d4e6d2ae-1d57-4ff9-9b0f-a1965b997520" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SalesRevenueNetMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_c33567b2-79d3-4658-b612-cf45976d7773" xlink:to="loc_us-gaap_SalesRevenueNetMember_d4e6d2ae-1d57-4ff9-9b0f-a1965b997520" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gentex.com/role/ComprehensiveIncomeAOCIRollforwardDetails" xlink:type="simple" xlink:href="gntx-20221231.xsd#ComprehensiveIncomeAOCIRollforwardDetails"/>
  <link:definitionLink xlink:role="http://www.gentex.com/role/ComprehensiveIncomeAOCIRollforwardDetails" xlink:type="extended" id="i3f3a8ae069674c7a9589913b8bd88f52_ComprehensiveIncomeAOCIRollforwardDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_c30aeb99-4076-45c1-a863-b3ff65a287ff" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_c2967b11-906a-40b3-9011-0a96822f9409" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AOCIAttributableToParentNetOfTaxRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_c30aeb99-4076-45c1-a863-b3ff65a287ff" xlink:to="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_c2967b11-906a-40b3-9011-0a96822f9409" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_6dcb0c91-3bf0-47dc-a2ae-74aeb773f6db" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_c2967b11-906a-40b3-9011-0a96822f9409" xlink:to="loc_us-gaap_StockholdersEquity_6dcb0c91-3bf0-47dc-a2ae-74aeb773f6db" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OciBeforeReclassificationsNetOfTaxAttributableToParent_53979e8f-434f-4b8e-a9dd-4f736116ad4b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OciBeforeReclassificationsNetOfTaxAttributableToParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_c2967b11-906a-40b3-9011-0a96822f9409" xlink:to="loc_us-gaap_OciBeforeReclassificationsNetOfTaxAttributableToParent_53979e8f-434f-4b8e-a9dd-4f736116ad4b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent_90055747-3fd6-4d37-89a7-61a892d1866b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_c2967b11-906a-40b3-9011-0a96822f9409" xlink:to="loc_us-gaap_ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent_90055747-3fd6-4d37-89a7-61a892d1866b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_5dcabf21-0084-432c-b5b4-e70d1c088247" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_c2967b11-906a-40b3-9011-0a96822f9409" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_5dcabf21-0084-432c-b5b4-e70d1c088247" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_7a80dadd-1cf5-4a56-9fba-ecc37b8f2d55" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockholdersEquity"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_38efcae0-d6b2-47e4-aad8-13b56308d72a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_c30aeb99-4076-45c1-a863-b3ff65a287ff" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_38efcae0-d6b2-47e4-aad8-13b56308d72a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_f86f9063-887d-4ddf-bb1c-ea547eaca7f7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_38efcae0-d6b2-47e4-aad8-13b56308d72a" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_f86f9063-887d-4ddf-bb1c-ea547eaca7f7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_f86f9063-887d-4ddf-bb1c-ea547eaca7f7_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_f86f9063-887d-4ddf-bb1c-ea547eaca7f7" xlink:to="loc_us-gaap_EquityComponentDomain_f86f9063-887d-4ddf-bb1c-ea547eaca7f7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_5079e9b0-491c-427c-9712-1468b2d41645" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_f86f9063-887d-4ddf-bb1c-ea547eaca7f7" xlink:to="loc_us-gaap_EquityComponentDomain_5079e9b0-491c-427c-9712-1468b2d41645" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_a8947b29-ed0d-4254-9acd-bcf545a1f0ea" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_5079e9b0-491c-427c-9712-1468b2d41645" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_a8947b29-ed0d-4254-9acd-bcf545a1f0ea" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedTranslationAdjustmentMember_257abeb7-0a2f-4ca4-a5ca-15d27711a91e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccumulatedTranslationAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_a8947b29-ed0d-4254-9acd-bcf545a1f0ea" xlink:to="loc_us-gaap_AccumulatedTranslationAdjustmentMember_257abeb7-0a2f-4ca4-a5ca-15d27711a91e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember_b661b1a5-940f-4801-893f-cadb8f4da6c2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_a8947b29-ed0d-4254-9acd-bcf545a1f0ea" xlink:to="loc_us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember_b661b1a5-940f-4801-893f-cadb8f4da6c2" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gentex.com/role/ComprehensiveIncomeReclassificationOutofAccumulatedOtherComprehensiveIncomeDetails" xlink:type="simple" xlink:href="gntx-20221231.xsd#ComprehensiveIncomeReclassificationOutofAccumulatedOtherComprehensiveIncomeDetails"/>
  <link:definitionLink xlink:role="http://www.gentex.com/role/ComprehensiveIncomeReclassificationOutofAccumulatedOtherComprehensiveIncomeDetails" xlink:type="extended" id="i57a88b74f3c54f429415875d9cf7dc22_ComprehensiveIncomeReclassificationOutofAccumulatedOtherComprehensiveIncomeDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems_1b9120a3-0ab2-4791-b313-fe94c8b7e77f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpense_8718dfb8-7ad8-476b-855e-56a3f76866d1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherNonoperatingIncomeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems_1b9120a3-0ab2-4791-b313-fe94c8b7e77f" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpense_8718dfb8-7ad8-476b-855e-56a3f76866d1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_6a22f5b2-8e52-425c-b9b7-e702c2c0954a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems_1b9120a3-0ab2-4791-b313-fe94c8b7e77f" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_6a22f5b2-8e52-425c-b9b7-e702c2c0954a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_1c93537c-b3d0-413a-9fd0-17c713f2269e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems_1b9120a3-0ab2-4791-b313-fe94c8b7e77f" xlink:to="loc_us-gaap_NetIncomeLoss_1c93537c-b3d0-413a-9fd0-17c713f2269e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTable_2b5b55dd-6d27-47e3-b51b-6d88b4eb357d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems_1b9120a3-0ab2-4791-b313-fe94c8b7e77f" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTable_2b5b55dd-6d27-47e3-b51b-6d88b4eb357d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_5b0cbe34-d8de-4bf4-9485-bff7ab182897" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTable_2b5b55dd-6d27-47e3-b51b-6d88b4eb357d" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_5b0cbe34-d8de-4bf4-9485-bff7ab182897" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_5b0cbe34-d8de-4bf4-9485-bff7ab182897_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_5b0cbe34-d8de-4bf4-9485-bff7ab182897" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_5b0cbe34-d8de-4bf4-9485-bff7ab182897_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_3aa6f5d5-a65f-4d3c-8730-9fe61945c744" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_5b0cbe34-d8de-4bf4-9485-bff7ab182897" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_3aa6f5d5-a65f-4d3c-8730-9fe61945c744" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember_917c3f71-c36f-46e6-903f-7fe9ed2d6f1a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_3aa6f5d5-a65f-4d3c-8730-9fe61945c744" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember_917c3f71-c36f-46e6-903f-7fe9ed2d6f1a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_5b68fb2a-f12b-4e76-a05e-0e40777bd781" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTable_2b5b55dd-6d27-47e3-b51b-6d88b4eb357d" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_5b68fb2a-f12b-4e76-a05e-0e40777bd781" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_5b68fb2a-f12b-4e76-a05e-0e40777bd781_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_5b68fb2a-f12b-4e76-a05e-0e40777bd781" xlink:to="loc_us-gaap_EquityComponentDomain_5b68fb2a-f12b-4e76-a05e-0e40777bd781_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_3d5487e3-78ea-46ab-82e1-297f1b3c434c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_5b68fb2a-f12b-4e76-a05e-0e40777bd781" xlink:to="loc_us-gaap_EquityComponentDomain_3d5487e3-78ea-46ab-82e1-297f1b3c434c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember_5802e5fd-0db6-4009-8672-21c37f370428" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_3d5487e3-78ea-46ab-82e1-297f1b3c434c" xlink:to="loc_us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember_5802e5fd-0db6-4009-8672-21c37f370428" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gentex.com/role/GoodwillandIntangibleAssetsNarrativeDetails" xlink:type="simple" xlink:href="gntx-20221231.xsd#GoodwillandIntangibleAssetsNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.gentex.com/role/GoodwillandIntangibleAssetsNarrativeDetails" xlink:type="extended" id="if0a4b7514f1d499f90d006587f3b1cd1_GoodwillandIntangibleAssetsNarrativeDetails">
    <link:loc xlink:type="locator" xlink:label="loc_gntx_ScheduleofFiniteLivedandIndefiniteLivedIntangibleAssetsLineItems_d83080c2-a30e-4050-ac3b-61ae2493d44b" xlink:href="gntx-20221231.xsd#gntx_ScheduleofFiniteLivedandIndefiniteLivedIntangibleAssetsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_6c782900-7b72-4b94-b42c-4bb8a6651738" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_Goodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_gntx_ScheduleofFiniteLivedandIndefiniteLivedIntangibleAssetsLineItems_d83080c2-a30e-4050-ac3b-61ae2493d44b" xlink:to="loc_us-gaap_Goodwill_6c782900-7b72-4b94-b42c-4bb8a6651738" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillAcquiredDuringPeriod_2a2bd468-7be1-40a4-9a79-e25c89c34f51" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_GoodwillAcquiredDuringPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_gntx_ScheduleofFiniteLivedandIndefiniteLivedIntangibleAssetsLineItems_d83080c2-a30e-4050-ac3b-61ae2493d44b" xlink:to="loc_us-gaap_GoodwillAcquiredDuringPeriod_2a2bd468-7be1-40a4-9a79-e25c89c34f51" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_eedd59b5-67af-4484-8a52-e8becd2c17e4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_gntx_ScheduleofFiniteLivedandIndefiniteLivedIntangibleAssetsLineItems_d83080c2-a30e-4050-ac3b-61ae2493d44b" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_eedd59b5-67af-4484-8a52-e8becd2c17e4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AmortizationOfIntangibleAssets_41cafe11-53d3-4fe2-a1da-b472917e2959" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AmortizationOfIntangibleAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_gntx_ScheduleofFiniteLivedandIndefiniteLivedIntangibleAssetsLineItems_d83080c2-a30e-4050-ac3b-61ae2493d44b" xlink:to="loc_us-gaap_AmortizationOfIntangibleAssets_41cafe11-53d3-4fe2-a1da-b472917e2959" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_27964194-5292-487f-a1db-d8640709f9c3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_gntx_ScheduleofFiniteLivedandIndefiniteLivedIntangibleAssetsLineItems_d83080c2-a30e-4050-ac3b-61ae2493d44b" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_27964194-5292-487f-a1db-d8640709f9c3" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths_d34b05a7-9470-4d8c-9eb1-5936113b408a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_gntx_ScheduleofFiniteLivedandIndefiniteLivedIntangibleAssetsLineItems_d83080c2-a30e-4050-ac3b-61ae2493d44b" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths_d34b05a7-9470-4d8c-9eb1-5936113b408a" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo_92896458-b1d0-4ed6-b404-21753011e91e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_gntx_ScheduleofFiniteLivedandIndefiniteLivedIntangibleAssetsLineItems_d83080c2-a30e-4050-ac3b-61ae2493d44b" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo_92896458-b1d0-4ed6-b404-21753011e91e" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree_52f5dd3b-f1b1-4487-8cf6-73955b951d41" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_gntx_ScheduleofFiniteLivedandIndefiniteLivedIntangibleAssetsLineItems_d83080c2-a30e-4050-ac3b-61ae2493d44b" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree_52f5dd3b-f1b1-4487-8cf6-73955b951d41" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour_1f872478-345e-48ac-97bc-e5688243dac9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_gntx_ScheduleofFiniteLivedandIndefiniteLivedIntangibleAssetsLineItems_d83080c2-a30e-4050-ac3b-61ae2493d44b" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour_1f872478-345e-48ac-97bc-e5688243dac9" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive_72b49b71-2f48-4b50-9271-7cd41c19088a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_gntx_ScheduleofFiniteLivedandIndefiniteLivedIntangibleAssetsLineItems_d83080c2-a30e-4050-ac3b-61ae2493d44b" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive_72b49b71-2f48-4b50-9271-7cd41c19088a" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_ScheduleofFiniteLivedandIndefiniteLivedIntangibleAssetsTable_4fe9301c-dd75-4229-a224-7d3791a31082" xlink:href="gntx-20221231.xsd#gntx_ScheduleofFiniteLivedandIndefiniteLivedIntangibleAssetsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_gntx_ScheduleofFiniteLivedandIndefiniteLivedIntangibleAssetsLineItems_d83080c2-a30e-4050-ac3b-61ae2493d44b" xlink:to="loc_gntx_ScheduleofFiniteLivedandIndefiniteLivedIntangibleAssetsTable_4fe9301c-dd75-4229-a224-7d3791a31082" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_f2023f9a-b3a9-4509-89e3-98528e40378a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_gntx_ScheduleofFiniteLivedandIndefiniteLivedIntangibleAssetsTable_4fe9301c-dd75-4229-a224-7d3791a31082" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_f2023f9a-b3a9-4509-89e3-98528e40378a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_f2023f9a-b3a9-4509-89e3-98528e40378a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_f2023f9a-b3a9-4509-89e3-98528e40378a" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_f2023f9a-b3a9-4509-89e3-98528e40378a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_09dead6e-518a-4770-a87e-c13be478c01e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_f2023f9a-b3a9-4509-89e3-98528e40378a" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_09dead6e-518a-4770-a87e-c13be478c01e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_HomeLinkMember_105433c5-3b4a-45c0-902b-cff8c469fd82" xlink:href="gntx-20221231.xsd#gntx_HomeLinkMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_09dead6e-518a-4770-a87e-c13be478c01e" xlink:to="loc_gntx_HomeLinkMember_105433c5-3b4a-45c0-902b-cff8c469fd82" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_VaporsensIncMember_cd2a4633-109e-4a6e-8d6e-177da5bb7e00" xlink:href="gntx-20221231.xsd#gntx_VaporsensIncMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_09dead6e-518a-4770-a87e-c13be478c01e" xlink:to="loc_gntx_VaporsensIncMember_cd2a4633-109e-4a6e-8d6e-177da5bb7e00" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_AirCraftGlassMember_9387683a-f290-4cc3-9980-41dbc7330a92" xlink:href="gntx-20221231.xsd#gntx_AirCraftGlassMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_09dead6e-518a-4770-a87e-c13be478c01e" xlink:to="loc_gntx_AirCraftGlassMember_9387683a-f290-4cc3-9980-41dbc7330a92" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_ArgilIncMember_2431bd61-bf99-4b4c-8e92-ec890d6aa639" xlink:href="gntx-20221231.xsd#gntx_ArgilIncMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_09dead6e-518a-4770-a87e-c13be478c01e" xlink:to="loc_gntx_ArgilIncMember_2431bd61-bf99-4b4c-8e92-ec890d6aa639" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_GuardianOpticalTechnologiesMember_a30d98c4-a156-4c52-94ce-ae10cc597daf" xlink:href="gntx-20221231.xsd#gntx_GuardianOpticalTechnologiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_09dead6e-518a-4770-a87e-c13be478c01e" xlink:to="loc_gntx_GuardianOpticalTechnologiesMember_a30d98c4-a156-4c52-94ce-ae10cc597daf" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_f0ea17b3-aaec-48fb-b207-e4b446296f65" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_gntx_ScheduleofFiniteLivedandIndefiniteLivedIntangibleAssetsTable_4fe9301c-dd75-4229-a224-7d3791a31082" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_f0ea17b3-aaec-48fb-b207-e4b446296f65" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_f0ea17b3-aaec-48fb-b207-e4b446296f65_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_f0ea17b3-aaec-48fb-b207-e4b446296f65" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_f0ea17b3-aaec-48fb-b207-e4b446296f65_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_123e020d-a853-4b05-8e03-8af8e6fb945a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_f0ea17b3-aaec-48fb-b207-e4b446296f65" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_123e020d-a853-4b05-8e03-8af8e6fb945a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_PatentsandOtherIntangibleAssetsMember_cd9f1272-ba9e-42c4-9b88-ab904d641a1f" xlink:href="gntx-20221231.xsd#gntx_PatentsandOtherIntangibleAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_123e020d-a853-4b05-8e03-8af8e6fb945a" xlink:to="loc_gntx_PatentsandOtherIntangibleAssetsMember_cd9f1272-ba9e-42c4-9b88-ab904d641a1f" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gentex.com/role/GoodwillandIntangibleAssetsScheduleofIntangibleAssetsDetails" xlink:type="simple" xlink:href="gntx-20221231.xsd#GoodwillandIntangibleAssetsScheduleofIntangibleAssetsDetails"/>
  <link:definitionLink xlink:role="http://www.gentex.com/role/GoodwillandIntangibleAssetsScheduleofIntangibleAssetsDetails" xlink:type="extended" id="id9a3d4f4673b46d79113b0bf969087b8_GoodwillandIntangibleAssetsScheduleofIntangibleAssetsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_gntx_ScheduleofFiniteLivedandIndefiniteLivedIntangibleAssetsLineItems_bd65e35c-5bbe-4bba-87b5-1a50a2444182" xlink:href="gntx-20221231.xsd#gntx_ScheduleofFiniteLivedandIndefiniteLivedIntangibleAssetsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill_e41067c4-92a6-4a2e-8c91-283b268ecde8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_gntx_ScheduleofFiniteLivedandIndefiniteLivedIntangibleAssetsLineItems_bd65e35c-5bbe-4bba-87b5-1a50a2444182" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill_e41067c4-92a6-4a2e-8c91-283b268ecde8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsGross_bc6442bf-5806-4065-97c1-f8c060a68eae" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_gntx_ScheduleofFiniteLivedandIndefiniteLivedIntangibleAssetsLineItems_bd65e35c-5bbe-4bba-87b5-1a50a2444182" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsGross_bc6442bf-5806-4065-97c1-f8c060a68eae" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_e28f3492-48dc-4d77-a40a-84c47f83670b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_gntx_ScheduleofFiniteLivedandIndefiniteLivedIntangibleAssetsLineItems_bd65e35c-5bbe-4bba-87b5-1a50a2444182" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_e28f3492-48dc-4d77-a40a-84c47f83670b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNet_8e2f2153-ee9b-4383-bf3f-7dfa9d167bdc" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_gntx_ScheduleofFiniteLivedandIndefiniteLivedIntangibleAssetsLineItems_bd65e35c-5bbe-4bba-87b5-1a50a2444182" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsNet_8e2f2153-ee9b-4383-bf3f-7dfa9d167bdc" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IntangibleAssetsGrossExcludingGoodwill_733fea18-5490-4a13-9c10-33819bfa8753" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IntangibleAssetsGrossExcludingGoodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_gntx_ScheduleofFiniteLivedandIndefiniteLivedIntangibleAssetsLineItems_bd65e35c-5bbe-4bba-87b5-1a50a2444182" xlink:to="loc_us-gaap_IntangibleAssetsGrossExcludingGoodwill_733fea18-5490-4a13-9c10-33819bfa8753" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_8c61c9fe-35f4-4b19-b09d-30b95678fe9b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_gntx_ScheduleofFiniteLivedandIndefiniteLivedIntangibleAssetsLineItems_bd65e35c-5bbe-4bba-87b5-1a50a2444182" xlink:to="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_8c61c9fe-35f4-4b19-b09d-30b95678fe9b" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_a3ed2376-f01d-4b7c-846a-e1fc4a1ba85c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_gntx_ScheduleofFiniteLivedandIndefiniteLivedIntangibleAssetsLineItems_bd65e35c-5bbe-4bba-87b5-1a50a2444182" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_a3ed2376-f01d-4b7c-846a-e1fc4a1ba85c" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_ScheduleofFiniteLivedandIndefiniteLivedIntangibleAssetsTable_f112fbb3-6459-472c-aca5-f167c1fe8b10" xlink:href="gntx-20221231.xsd#gntx_ScheduleofFiniteLivedandIndefiniteLivedIntangibleAssetsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_gntx_ScheduleofFiniteLivedandIndefiniteLivedIntangibleAssetsLineItems_bd65e35c-5bbe-4bba-87b5-1a50a2444182" xlink:to="loc_gntx_ScheduleofFiniteLivedandIndefiniteLivedIntangibleAssetsTable_f112fbb3-6459-472c-aca5-f167c1fe8b10" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_5351d4da-fe94-4d0f-9f98-f426ab448324" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_gntx_ScheduleofFiniteLivedandIndefiniteLivedIntangibleAssetsTable_f112fbb3-6459-472c-aca5-f167c1fe8b10" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_5351d4da-fe94-4d0f-9f98-f426ab448324" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_5351d4da-fe94-4d0f-9f98-f426ab448324_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_5351d4da-fe94-4d0f-9f98-f426ab448324" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_5351d4da-fe94-4d0f-9f98-f426ab448324_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_95712e32-a8c2-46e9-b805-6cf4593b8727" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_5351d4da-fe94-4d0f-9f98-f426ab448324" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_95712e32-a8c2-46e9-b805-6cf4593b8727" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_HomeLinkMember_ccd960d5-2c37-418a-83bc-a6283b0b2119" xlink:href="gntx-20221231.xsd#gntx_HomeLinkMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_95712e32-a8c2-46e9-b805-6cf4593b8727" xlink:to="loc_gntx_HomeLinkMember_ccd960d5-2c37-418a-83bc-a6283b0b2119" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_VaporsensIncMember_a24ebe3a-6f18-49ed-8c07-7b055a73a6ba" xlink:href="gntx-20221231.xsd#gntx_VaporsensIncMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_95712e32-a8c2-46e9-b805-6cf4593b8727" xlink:to="loc_gntx_VaporsensIncMember_a24ebe3a-6f18-49ed-8c07-7b055a73a6ba" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_ArgilIncMember_5b1655c3-7543-486a-ad4c-6c68f7c94e76" xlink:href="gntx-20221231.xsd#gntx_ArgilIncMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_95712e32-a8c2-46e9-b805-6cf4593b8727" xlink:to="loc_gntx_ArgilIncMember_5b1655c3-7543-486a-ad4c-6c68f7c94e76" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_AirCraftglassMember_a9b2c2ee-9e7e-4db8-a2bd-82e3b6593ece" xlink:href="gntx-20221231.xsd#gntx_AirCraftglassMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_95712e32-a8c2-46e9-b805-6cf4593b8727" xlink:to="loc_gntx_AirCraftglassMember_a9b2c2ee-9e7e-4db8-a2bd-82e3b6593ece" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_GuardianOpticalTechnologiesMember_3140d694-2af0-4450-b102-e1363939129c" xlink:href="gntx-20221231.xsd#gntx_GuardianOpticalTechnologiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_95712e32-a8c2-46e9-b805-6cf4593b8727" xlink:to="loc_gntx_GuardianOpticalTechnologiesMember_3140d694-2af0-4450-b102-e1363939129c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_21aefae3-c626-4f41-ada0-d355550b48b4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_gntx_ScheduleofFiniteLivedandIndefiniteLivedIntangibleAssetsTable_f112fbb3-6459-472c-aca5-f167c1fe8b10" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_21aefae3-c626-4f41-ada0-d355550b48b4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_21aefae3-c626-4f41-ada0-d355550b48b4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_21aefae3-c626-4f41-ada0-d355550b48b4" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_21aefae3-c626-4f41-ada0-d355550b48b4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_fb5b72a3-162c-4efa-8f91-438857203bbb" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_21aefae3-c626-4f41-ada0-d355550b48b4" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_fb5b72a3-162c-4efa-8f91-438857203bbb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TrademarksAndTradeNamesMember_78819a20-cb7a-48d6-83f0-863bbfcf1997" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TrademarksAndTradeNamesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_fb5b72a3-162c-4efa-8f91-438857203bbb" xlink:to="loc_us-gaap_TrademarksAndTradeNamesMember_78819a20-cb7a-48d6-83f0-863bbfcf1997" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LicensingAgreementsMember_cea2d9aa-a904-4e35-85ed-38619091d153" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LicensingAgreementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_fb5b72a3-162c-4efa-8f91-438857203bbb" xlink:to="loc_us-gaap_LicensingAgreementsMember_cea2d9aa-a904-4e35-85ed-38619091d153" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InProcessResearchAndDevelopmentMember_ca646119-d8a2-45bb-939e-cd8ca0592f8f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InProcessResearchAndDevelopmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_fb5b72a3-162c-4efa-8f91-438857203bbb" xlink:to="loc_us-gaap_InProcessResearchAndDevelopmentMember_ca646119-d8a2-45bb-939e-cd8ca0592f8f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_59d803e8-3534-4b66-b86d-e9490f0e0a86" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_gntx_ScheduleofFiniteLivedandIndefiniteLivedIntangibleAssetsTable_f112fbb3-6459-472c-aca5-f167c1fe8b10" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_59d803e8-3534-4b66-b86d-e9490f0e0a86" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_59d803e8-3534-4b66-b86d-e9490f0e0a86_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_59d803e8-3534-4b66-b86d-e9490f0e0a86" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_59d803e8-3534-4b66-b86d-e9490f0e0a86_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_d8b76756-2c32-42cf-a5f8-92ceca273f2f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_59d803e8-3534-4b66-b86d-e9490f0e0a86" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_d8b76756-2c32-42cf-a5f8-92ceca273f2f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DevelopedTechnologyRightsMember_31d2fdb9-049b-4e94-b860-1fa84e4a57dc" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DevelopedTechnologyRightsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_d8b76756-2c32-42cf-a5f8-92ceca273f2f" xlink:to="loc_us-gaap_DevelopedTechnologyRightsMember_31d2fdb9-049b-4e94-b860-1fa84e4a57dc" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerContractsMember_b5857875-d4e8-4e82-ae1e-14e555c187bb" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CustomerContractsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_d8b76756-2c32-42cf-a5f8-92ceca273f2f" xlink:to="loc_us-gaap_CustomerContractsMember_b5857875-d4e8-4e82-ae1e-14e555c187bb" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gentex.com/role/RevenueDetails" xlink:type="simple" xlink:href="gntx-20221231.xsd#RevenueDetails"/>
  <link:definitionLink xlink:role="http://www.gentex.com/role/RevenueDetails" xlink:type="extended" id="id09bb99a93464e9781395f4581c72611_RevenueDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_4dd33643-2429-4251-a404-ba857bd921ef" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DisaggregationOfRevenueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_668b7117-273a-477e-8d5c-d756854a1838" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_4dd33643-2429-4251-a404-ba857bd921ef" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_668b7117-273a-477e-8d5c-d756854a1838" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_RevenuefromContractwithCustomerPaymentTerms_67774e89-f8b9-46d5-aa6a-4a82caee68b5" xlink:href="gntx-20221231.xsd#gntx_RevenuefromContractwithCustomerPaymentTerms"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_4dd33643-2429-4251-a404-ba857bd921ef" xlink:to="loc_gntx_RevenuefromContractwithCustomerPaymentTerms_67774e89-f8b9-46d5-aa6a-4a82caee68b5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_c7a4f9c4-213f-4c84-ad6a-a6ba40059896" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DisaggregationOfRevenueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_4dd33643-2429-4251-a404-ba857bd921ef" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_c7a4f9c4-213f-4c84-ad6a-a6ba40059896" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis_80064fb0-dac2-45d1-974a-f3f4c22b346d" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_StatementGeographicalAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_c7a4f9c4-213f-4c84-ad6a-a6ba40059896" xlink:to="loc_srt_StatementGeographicalAxis_80064fb0-dac2-45d1-974a-f3f4c22b346d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_80064fb0-dac2-45d1-974a-f3f4c22b346d_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_80064fb0-dac2-45d1-974a-f3f4c22b346d" xlink:to="loc_srt_SegmentGeographicalDomain_80064fb0-dac2-45d1-974a-f3f4c22b346d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_02faeceb-792c-40d1-a9e4-8c76f0e1d3ee" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_80064fb0-dac2-45d1-974a-f3f4c22b346d" xlink:to="loc_srt_SegmentGeographicalDomain_02faeceb-792c-40d1-a9e4-8c76f0e1d3ee" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_US_85182ee8-ba8c-4e65-be2a-cc72b2ce8ee5" xlink:href="https://xbrl.sec.gov/country/2022/country-2022.xsd#country_US"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_02faeceb-792c-40d1-a9e4-8c76f0e1d3ee" xlink:to="loc_country_US_85182ee8-ba8c-4e65-be2a-cc72b2ce8ee5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_DE_e7894f90-ea13-4ef1-b88b-e99b1cd24796" xlink:href="https://xbrl.sec.gov/country/2022/country-2022.xsd#country_DE"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_02faeceb-792c-40d1-a9e4-8c76f0e1d3ee" xlink:to="loc_country_DE_e7894f90-ea13-4ef1-b88b-e99b1cd24796" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_JP_fee63328-2396-401c-8f42-fef69ac2d793" xlink:href="https://xbrl.sec.gov/country/2022/country-2022.xsd#country_JP"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_02faeceb-792c-40d1-a9e4-8c76f0e1d3ee" xlink:to="loc_country_JP_fee63328-2396-401c-8f42-fef69ac2d793" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_MX_1a3627d7-95d5-4edd-bb47-cea287813c36" xlink:href="https://xbrl.sec.gov/country/2022/country-2022.xsd#country_MX"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_02faeceb-792c-40d1-a9e4-8c76f0e1d3ee" xlink:to="loc_country_MX_1a3627d7-95d5-4edd-bb47-cea287813c36" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_OtherCountriesMember_b2220d30-d00c-431c-9c57-f6975b293109" xlink:href="gntx-20221231.xsd#gntx_OtherCountriesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_02faeceb-792c-40d1-a9e4-8c76f0e1d3ee" xlink:to="loc_gntx_OtherCountriesMember_b2220d30-d00c-431c-9c57-f6975b293109" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_d4f7c071-69f7-41f4-8ecd-422fbcad9136" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_c7a4f9c4-213f-4c84-ad6a-a6ba40059896" xlink:to="loc_srt_ProductOrServiceAxis_d4f7c071-69f7-41f4-8ecd-422fbcad9136" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_d4f7c071-69f7-41f4-8ecd-422fbcad9136_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_d4f7c071-69f7-41f4-8ecd-422fbcad9136" xlink:to="loc_srt_ProductsAndServicesDomain_d4f7c071-69f7-41f4-8ecd-422fbcad9136_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_0836f4c0-5f43-49b8-94de-ef1323607901" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_d4f7c071-69f7-41f4-8ecd-422fbcad9136" xlink:to="loc_srt_ProductsAndServicesDomain_0836f4c0-5f43-49b8-94de-ef1323607901" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_AutomotiveProductsMember_c1752da5-ef61-4f4d-b651-c9686190c838" xlink:href="gntx-20221231.xsd#gntx_AutomotiveProductsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_0836f4c0-5f43-49b8-94de-ef1323607901" xlink:to="loc_gntx_AutomotiveProductsMember_c1752da5-ef61-4f4d-b651-c9686190c838" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_AutomotiveMirrorsElectronicsMember_28fbc1c7-0cc5-4cee-8bbd-2d69a042cbdd" xlink:href="gntx-20221231.xsd#gntx_AutomotiveMirrorsElectronicsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_gntx_AutomotiveProductsMember_c1752da5-ef61-4f4d-b651-c9686190c838" xlink:to="loc_gntx_AutomotiveMirrorsElectronicsMember_28fbc1c7-0cc5-4cee-8bbd-2d69a042cbdd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_HomeLinkModulesMember_704dacc9-ccb8-4e64-8ef0-91740b315d4d" xlink:href="gntx-20221231.xsd#gntx_HomeLinkModulesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_gntx_AutomotiveProductsMember_c1752da5-ef61-4f4d-b651-c9686190c838" xlink:to="loc_gntx_HomeLinkModulesMember_704dacc9-ccb8-4e64-8ef0-91740b315d4d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_OtherProductsMember_95da5c90-bfc7-493a-b68d-5f9a7507d41a" xlink:href="gntx-20221231.xsd#gntx_OtherProductsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_0836f4c0-5f43-49b8-94de-ef1323607901" xlink:to="loc_gntx_OtherProductsMember_95da5c90-bfc7-493a-b68d-5f9a7507d41a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_FireProtectionProductsMember_0f9066cc-7339-4737-bebf-b995ea22a0ef" xlink:href="gntx-20221231.xsd#gntx_FireProtectionProductsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_gntx_OtherProductsMember_95da5c90-bfc7-493a-b68d-5f9a7507d41a" xlink:to="loc_gntx_FireProtectionProductsMember_0f9066cc-7339-4737-bebf-b995ea22a0ef" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_WindowsProductsMember_14c5e44c-02de-40e3-b029-7ed441dde1cb" xlink:href="gntx-20221231.xsd#gntx_WindowsProductsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_gntx_OtherProductsMember_95da5c90-bfc7-493a-b68d-5f9a7507d41a" xlink:to="loc_gntx_WindowsProductsMember_14c5e44c-02de-40e3-b029-7ed441dde1cb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_NanofiberProductsMember_bef8b287-cf9e-4e7d-b2cd-f13847d2161e" xlink:href="gntx-20221231.xsd#gntx_NanofiberProductsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_gntx_WindowsProductsMember_14c5e44c-02de-40e3-b029-7ed441dde1cb" xlink:to="loc_gntx_NanofiberProductsMember_bef8b287-cf9e-4e7d-b2cd-f13847d2161e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_DimmableAircraftWindowsMember_65d39083-aae8-4578-b8b0-b72378d58967" xlink:href="gntx-20221231.xsd#gntx_DimmableAircraftWindowsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_gntx_WindowsProductsMember_14c5e44c-02de-40e3-b029-7ed441dde1cb" xlink:to="loc_gntx_DimmableAircraftWindowsMember_65d39083-aae8-4578-b8b0-b72378d58967" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_13742e5a-7635-45b6-8294-eaa3e6c2a6a8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_c7a4f9c4-213f-4c84-ad6a-a6ba40059896" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_13742e5a-7635-45b6-8294-eaa3e6c2a6a8" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_13742e5a-7635-45b6-8294-eaa3e6c2a6a8_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_13742e5a-7635-45b6-8294-eaa3e6c2a6a8" xlink:to="loc_us-gaap_SegmentDomain_13742e5a-7635-45b6-8294-eaa3e6c2a6a8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_8d8a0550-5b11-4ac7-8dbf-6444016f2f22" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_13742e5a-7635-45b6-8294-eaa3e6c2a6a8" xlink:to="loc_us-gaap_SegmentDomain_8d8a0550-5b11-4ac7-8dbf-6444016f2f22" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_AutomotiveSegmentMember_2f99dfdb-81d7-4ebf-8bc5-e38fcfa5d239" xlink:href="gntx-20221231.xsd#gntx_AutomotiveSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_8d8a0550-5b11-4ac7-8dbf-6444016f2f22" xlink:to="loc_gntx_AutomotiveSegmentMember_2f99dfdb-81d7-4ebf-8bc5-e38fcfa5d239" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllOtherSegmentsMember_2d4df482-7115-4d59-9206-aec8383174ab" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AllOtherSegmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_8d8a0550-5b11-4ac7-8dbf-6444016f2f22" xlink:to="loc_us-gaap_AllOtherSegmentsMember_2d4df482-7115-4d59-9206-aec8383174ab" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_9570ce9f-e445-4ffb-a3ba-19e9561ec50f" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_c7a4f9c4-213f-4c84-ad6a-a6ba40059896" xlink:to="loc_srt_RangeAxis_9570ce9f-e445-4ffb-a3ba-19e9561ec50f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_9570ce9f-e445-4ffb-a3ba-19e9561ec50f_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_9570ce9f-e445-4ffb-a3ba-19e9561ec50f" xlink:to="loc_srt_RangeMember_9570ce9f-e445-4ffb-a3ba-19e9561ec50f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_397cbdfd-2de4-4cf5-b473-963bffdf3234" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_9570ce9f-e445-4ffb-a3ba-19e9561ec50f" xlink:to="loc_srt_RangeMember_397cbdfd-2de4-4cf5-b473-963bffdf3234" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_d8718a78-7952-4dcc-873f-e1f98fcfb67f" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_397cbdfd-2de4-4cf5-b473-963bffdf3234" xlink:to="loc_srt_MinimumMember_d8718a78-7952-4dcc-873f-e1f98fcfb67f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_81bf128e-f3e3-4bbd-82b1-e9ddc842cba3" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_397cbdfd-2de4-4cf5-b473-963bffdf3234" xlink:to="loc_srt_MaximumMember_81bf128e-f3e3-4bbd-82b1-e9ddc842cba3" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gentex.com/role/AcquisitionsDetails" xlink:type="simple" xlink:href="gntx-20221231.xsd#AcquisitionsDetails"/>
  <link:definitionLink xlink:role="http://www.gentex.com/role/AcquisitionsDetails" xlink:type="extended" id="i1a4bef769e5c4953aea11d286c51e5cb_AcquisitionsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_f453ec50-d20a-47f2-9b32-3484437f62fe" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessAcquisitionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_BusinessAcquisitionAgreementValue_a0998b59-8aaa-4d2f-a53a-7d26c2855563" xlink:href="gntx-20221231.xsd#gntx_BusinessAcquisitionAgreementValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_f453ec50-d20a-47f2-9b32-3484437f62fe" xlink:to="loc_gntx_BusinessAcquisitionAgreementValue_a0998b59-8aaa-4d2f-a53a-7d26c2855563" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired_20df2546-d645-4d8c-bba2-3ef8bf8c271a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_f453ec50-d20a-47f2-9b32-3484437f62fe" xlink:to="loc_us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired_20df2546-d645-4d8c-bba2-3ef8bf8c271a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_9733e1fe-d391-4619-aa37-0eb861cbdae8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_f453ec50-d20a-47f2-9b32-3484437f62fe" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_9733e1fe-d391-4619-aa37-0eb861cbdae8" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_3366ff5a-6bc4-43a8-9efa-cd1d16a27f15" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_9733e1fe-d391-4619-aa37-0eb861cbdae8" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_3366ff5a-6bc4-43a8-9efa-cd1d16a27f15" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_3366ff5a-6bc4-43a8-9efa-cd1d16a27f15_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_3366ff5a-6bc4-43a8-9efa-cd1d16a27f15" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_3366ff5a-6bc4-43a8-9efa-cd1d16a27f15_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_37dbed07-5a2c-4f4f-93ee-325794a18c6d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_3366ff5a-6bc4-43a8-9efa-cd1d16a27f15" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_37dbed07-5a2c-4f4f-93ee-325794a18c6d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_GuardianOpticalTechnologiesMember_82700edd-245c-4d52-bb66-2057d36f7d35" xlink:href="gntx-20221231.xsd#gntx_GuardianOpticalTechnologiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_37dbed07-5a2c-4f4f-93ee-325794a18c6d" xlink:to="loc_gntx_GuardianOpticalTechnologiesMember_82700edd-245c-4d52-bb66-2057d36f7d35" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gentex.com/role/SubsequentEventsDetails" xlink:type="simple" xlink:href="gntx-20221231.xsd#SubsequentEventsDetails"/>
  <link:definitionLink xlink:role="http://www.gentex.com/role/SubsequentEventsDetails" xlink:type="extended" id="if0a74daab3ce4a02853e75026b6bc65a_SubsequentEventsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventLineItems_63ef9995-d7e4-4844-9ba8-b4629e6f9b00" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SubsequentEventLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTerm_388a5553-4215-4534-b304-f96c6738f0bd" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_63ef9995-d7e4-4844-9ba8-b4629e6f9b00" xlink:to="loc_us-gaap_DebtInstrumentTerm_388a5553-4215-4534-b304-f96c6738f0bd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_49e4deeb-41fb-49d5-857d-0fb5f485e5fa" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_63ef9995-d7e4-4844-9ba8-b4629e6f9b00" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_49e4deeb-41fb-49d5-857d-0fb5f485e5fa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_DebtInstrumentAdditionalBorrowingsAvailableFaceAmount_2a15705c-6ab3-47c3-be45-ede2dc2af4b3" xlink:href="gntx-20221231.xsd#gntx_DebtInstrumentAdditionalBorrowingsAvailableFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_63ef9995-d7e4-4844-9ba8-b4629e6f9b00" xlink:to="loc_gntx_DebtInstrumentAdditionalBorrowingsAvailableFaceAmount_2a15705c-6ab3-47c3-be45-ede2dc2af4b3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTable_51d67650-6b70-4e5a-85bb-ba1ddb738332" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SubsequentEventTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SubsequentEventLineItems_63ef9995-d7e4-4844-9ba8-b4629e6f9b00" xlink:to="loc_us-gaap_SubsequentEventTable_51d67650-6b70-4e5a-85bb-ba1ddb738332" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_0dd3b5d8-3e73-4c40-9240-c4e84acfbc29" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_51d67650-6b70-4e5a-85bb-ba1ddb738332" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_0dd3b5d8-3e73-4c40-9240-c4e84acfbc29" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_0dd3b5d8-3e73-4c40-9240-c4e84acfbc29_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_0dd3b5d8-3e73-4c40-9240-c4e84acfbc29" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_0dd3b5d8-3e73-4c40-9240-c4e84acfbc29_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_43eb30a2-4b8e-4ab9-bc80-0219d731b1b7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_0dd3b5d8-3e73-4c40-9240-c4e84acfbc29" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_43eb30a2-4b8e-4ab9-bc80-0219d731b1b7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_12101336-514b-40c5-815b-710abccf022d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_43eb30a2-4b8e-4ab9-bc80-0219d731b1b7" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_12101336-514b-40c5-815b-710abccf022d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LetterOfCreditMember_a9922209-c48a-440c-a23a-fc443ada6b66" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LetterOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_43eb30a2-4b8e-4ab9-bc80-0219d731b1b7" xlink:to="loc_us-gaap_LetterOfCreditMember_a9922209-c48a-440c-a23a-fc443ada6b66" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_SwingLoansMember_0a53d094-2993-4170-8702-060ec17ab389" xlink:href="gntx-20221231.xsd#gntx_SwingLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_43eb30a2-4b8e-4ab9-bc80-0219d731b1b7" xlink:to="loc_gntx_SwingLoansMember_0a53d094-2993-4170-8702-060ec17ab389" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_70348e97-8682-49ee-aa66-96c44b71c060" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SubsequentEventTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_51d67650-6b70-4e5a-85bb-ba1ddb738332" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_70348e97-8682-49ee-aa66-96c44b71c060" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_70348e97-8682-49ee-aa66-96c44b71c060_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_70348e97-8682-49ee-aa66-96c44b71c060" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_70348e97-8682-49ee-aa66-96c44b71c060_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_c0e5ea71-890b-4b95-aff6-de0fb6142eac" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_70348e97-8682-49ee-aa66-96c44b71c060" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_c0e5ea71-890b-4b95-aff6-de0fb6142eac" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventMember_8a8bcfe5-a9f9-4f99-a2f4-c2247f4e377e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SubsequentEventMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_c0e5ea71-890b-4b95-aff6-de0fb6142eac" xlink:to="loc_us-gaap_SubsequentEventMember_8a8bcfe5-a9f9-4f99-a2f4-c2247f4e377e" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://fasb.org/us-gaap/role/eedm/ExtensibleEnumerationLists" xlink:type="simple" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-roles-2022.xsd#eedm"/>
  <link:definitionLink xlink:role="http://fasb.org/us-gaap/role/eedm/ExtensibleEnumerationLists" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilitiesAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_gntx_PatentandOtherAssetsNet_ebf22d2c-d15c-4558-b7eb-cd6ee6e8d7c8" xlink:href="gntx-20221231.xsd#gntx_PatentandOtherAssetsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract" xlink:to="loc_gntx_PatentandOtherAssetsNet_ebf22d2c-d15c-4558-b7eb-cd6ee6e8d7c8" xlink:type="arc" order="1"/>
  </link:definitionLink>
</link:linkbase>
