<?xml version="1.0" encoding="utf-8"?>
<!--XBRL document created with Toppan Merrill Bridge  10.5.0.8 -->
<!--Based on XBRL 2.1-->
<!--Created on: 3/1/2024 9:12:46 PM-->
<!--Modified on: 3/1/2024 9:12:46 PM-->
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    <loc xlink:type="locator" xlink:href="wst-20240423.xsd#wst_EquityAwardsValueInCompensationTableForApplicableYearMember" xlink:label="wst_EquityAwardsValueInCompensationTableForApplicableYearMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="wst_EquityAwardsValueInCompensationTableForApplicableYearMember" xlink:to="wst_EquityAwardsValueInCompensationTableForApplicableYearMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="wst_EquityAwardsValueInCompensationTableForApplicableYearMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">This member presents the adjustment (deduction) for equity awards value from summary compensation table.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="wst_EquityAwardsValueInCompensationTableForApplicableYearMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Equity Awards Value in Compensation Table for the Applicable Year [Member]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="wst_EquityAwardsAdjustmentsYearEndFairValueOfAwardsGrantedInCurrentYearMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">This member presents the equity awards adjustments on the year-end fair value of any equity awards granted in the applicable year that are outstanding and unvested as of the end of the year.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="wst_EquityAwardsAdjustmentsYearEndFairValueOfAwardsGrantedInCurrentYearMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Equity Awards Adjustments Year End Fair Value of Awards Granted in Current Year [Member]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="wst_EquityAwardsAdjustmentsChangeInFairValueAsOfYearEndOfOutstandingAndUnvestedAwardsGrantedInPriorYearsMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">This member presents the equity awards adjustments on the change in fair value from the end of the prior fiscal year of any awards granted in prior years that are outstanding and unvested as of the end of the applicable year.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="wst_EquityAwardsAdjustmentsChangeInFairValueAsOfYearEndOfOutstandingAndUnvestedAwardsGrantedInPriorYearsMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Equity Awards Adjustments Change in Fair Value as of Year End of Outstanding and Unvested Awards Granted in Prior Years [Member]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="wst_EquityAwardsAdjustmentsChangeInFairValueAsOfVestingDateOfPriorYearAwardsVestedDuringCurrentYearMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">This member presents the equity awards adjustments on the change in fair value (as of vesting date) of prior year awards vested during current year.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="wst_EquityAwardsAdjustmentsChangeInFairValueAsOfVestingDateOfPriorYearAwardsVestedDuringCurrentYearMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Equity Awards Adjustments Change in Fair Value as of Vesting Date of Prior Year Awards Vested During Current Year [Member]</label>
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    <loc xlink:type="locator" xlink:href="wst-20240423.xsd#wst_PensionValueInCompensationTableForApplicableYearMember" xlink:label="wst_PensionValueInCompensationTableForApplicableYearMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="wst_PensionValueInCompensationTableForApplicableYearMember" xlink:to="wst_PensionValueInCompensationTableForApplicableYearMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="wst_PensionValueInCompensationTableForApplicableYearMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">This member presents the adjustment (deduction) for pension value from summary compensation table.</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="wst_PensionAdjustmentsMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">This member presents the total pension adjustments, which may be comprised of adjustments for service cost and prior service cost.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="wst_PensionAdjustmentsMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Pension Adjustments [Member]</label>
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    <loc xlink:type="locator" xlink:href="wst-20240423.xsd#wst_EquityAwardsAdjustmentsYearEndFairValueOfAwardsGrantedAndVestedInCurrentYearMember" xlink:label="wst_EquityAwardsAdjustmentsYearEndFairValueOfAwardsGrantedAndVestedInCurrentYearMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="wst_EquityAwardsAdjustmentsYearEndFairValueOfAwardsGrantedAndVestedInCurrentYearMember" xlink:to="wst_EquityAwardsAdjustmentsYearEndFairValueOfAwardsGrantedAndVestedInCurrentYearMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="wst_EquityAwardsAdjustmentsYearEndFairValueOfAwardsGrantedAndVestedInCurrentYearMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">This member presents the equity awards adjustments on the year-end fair value of any equity awards granted in the applicable year that are outstanding and vested as of the end of the year.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="wst_EquityAwardsAdjustmentsYearEndFairValueOfAwardsGrantedAndVestedInCurrentYearMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Equity Awards Adjustments Year End Fair Value of Awards Granted and Vested in Current Year [Member]</label>
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    <loc xlink:type="locator" xlink:href="wst-20240423.xsd#wst_EquityAwardsAdjustmentsAdjustmentsForEquityAwardsFailedToMeetPerformanceConditionsMember" xlink:label="wst_EquityAwardsAdjustmentsAdjustmentsForEquityAwardsFailedToMeetPerformanceConditionsMember" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="wst_EquityAwardsAdjustmentsAdjustmentsForEquityAwardsFailedToMeetPerformanceConditionsMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Equity Awards Adjustments, Adjustments for Equity Awards Failed to Meet Performance Conditions [Member]</label>
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