<SEC-DOCUMENT>0001628280-26-020099.txt : 20260320
<SEC-HEADER>0001628280-26-020099.hdr.sgml : 20260320
<ACCEPTANCE-DATETIME>20260320131544
ACCESSION NUMBER:		0001628280-26-020099
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20260318
FILED AS OF DATE:		20260320
DATE AS OF CHANGE:		20260320

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Fairweather Carol
		CENTRAL INDEX KEY:			0002029261
		ORGANIZATION NAME:           	

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-42161
		FILM NUMBER:		26777418

	MAIL ADDRESS:	
		STREET 1:		BEECH HILL
		STREET 2:		CLONSKEAGH
		CITY:			DUBLIN 4
		STATE:			L2
		ZIP:			D04 N2R2

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Smurfit Westrock plc
		CENTRAL INDEX KEY:			0002005951
		STANDARD INDUSTRIAL CLASSIFICATION:	PAPERBOARD CONTAINERS & BOXES [2650]
		ORGANIZATION NAME:           	04 Manufacturing
		EIN:				000000000
		STATE OF INCORPORATION:			L2
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		ADDRESS IS A NON US LOCATION: 	YES
		STREET 1:		BEECH HILL
		STREET 2:		CLONSKEAGH
		CITY:			DUBLIN 4
		PROVINCE COUNTRY:   	L2
		ZIP:			D04 N2R2
		BUSINESS PHONE:		353 1 202 7000

	MAIL ADDRESS:	
		ADDRESS IS A NON US LOCATION: 	YES
		STREET 1:		BEECH HILL
		STREET 2:		CLONSKEAGH
		CITY:			DUBLIN 4
		PROVINCE COUNTRY:   	L2
		ZIP:			D04 N2R2

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	Smurfit WestRock plc
		DATE OF NAME CHANGE:	20240628

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	Smurfit WestRock Ltd
		DATE OF NAME CHANGE:	20231226
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wk-form4_1774026941.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0609</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2026-03-18</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0002005951</issuerCik>
        <issuerName>Smurfit Westrock plc</issuerName>
        <issuerTradingSymbol>SW</issuerTradingSymbol>
        <issuerForeignTradingSymbol></issuerForeignTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0002029261</rptOwnerCik>
            <rptOwnerName>Fairweather Carol</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>BEECH HILL, CLONSKEAGH</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>DUBLIN 4</rptOwnerCity>
            <rptOwnerState></rptOwnerState>
            <rptOwnerZipCode>D04 N2R2</rptOwnerZipCode>
            <rptOwnerStateDescription>IRELAND</rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Ordinary Shares</value>
            </securityTitle>
            <transactionDate>
                <value>2026-03-18</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>51</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>9230</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">In accordance with the terms of the restricted stock unit award, additional restricted stock units accrued as dividend equivalents in connection with the Issuer's payment of a quarterly dividend of
$0.4523 per ordinary share. Such additional restricted stock units are subject to the same terms and conditions as the underlying award. Each restricted stock unit represents the right to receive one
ordinary share.</footnote>
        <footnote id="F2">Includes 4,422 restricted stock units which will vest on the earlier of (i) May 2, 2026 or (ii) the date of the next annual meeting of Smurfit Westrock plc's stockholders.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Ciara O'Riordan, attorney-in-fact pursuant for Carol Fairweather</signatureName>
        <signatureDate>2026-03-20</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
