<?xml version="1.0" encoding="utf-8"?>
<!--Generated by DFIN XBRL Instance Document - http://www.dfinsolutions.com/ - Version R3.0 - on 28-April-2023 [05:56:18] {PM}-->
<linkbase xmlns="http://www.xbrl.org/2003/linkbase" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xlink="http://www.w3.org/1999/xlink" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" xmlns:xbrldt="http://xbrl.org/2005/xbrldt">
<roleRef xlink:type="simple" xlink:href="vtrs-20221231.xsd#AuditInformation" roleURI="http://www.upjohnInc.com/role/AuditInformation" />
<roleRef xlink:type="simple" xlink:href="vtrs-20221231.xsd#Cover" roleURI="http://www.upjohnInc.com/role/Cover" />
<arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all" />
<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" />
<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" />
<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" />
<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" />
<arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/notAll" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#notAll" />
<definitionLink xlink:type="extended" xlink:role="http://www.upjohnInc.com/role/AuditInformation">
<loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_AuditorLineItems" xlink:label="loc_dei_AuditorLineItems_1398381" />
<loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_AuditorTable" xlink:label="loc_dei_AuditorTable_1398380" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_dei_AuditorLineItems_1398381" xlink:to="loc_dei_AuditorTable_1398380" xbrldt:contextElement="segment" xbrldt:closed="true" use="optional" order="1" />
<loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_AuditorName" xlink:label="loc_dei_AuditorName_1398382" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_AuditorLineItems_1398381" xlink:to="loc_dei_AuditorName_1398382" use="optional" order="2" />
<loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_AuditorLocation" xlink:label="loc_dei_AuditorLocation_1398383" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_AuditorLineItems_1398381" xlink:to="loc_dei_AuditorLocation_1398383" use="optional" order="3" />
<loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_AuditorFirmId" xlink:label="loc_dei_AuditorFirmId_1398385" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_AuditorLineItems_1398381" xlink:to="loc_dei_AuditorFirmId_1398385" use="optional" order="4" />
</definitionLink>
</linkbase>
