<SEC-DOCUMENT>0001448352-25-000005.txt : 20250820
<SEC-HEADER>0001448352-25-000005.hdr.sgml : 20250820
<ACCEPTANCE-DATETIME>20250820162946
ACCESSION NUMBER:		0001448352-25-000005
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20250819
FILED AS OF DATE:		20250820
DATE AS OF CHANGE:		20250820

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			BUSTER H CLIFFORD III
		CENTRAL INDEX KEY:			0001448352
		ORGANIZATION NAME:           	

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-31922
		FILM NUMBER:		251237166

	MAIL ADDRESS:	
		STREET 1:		1000 TEMPUR WAY
		CITY:			LEXINGTON
		STATE:			KY
		ZIP:			74135

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			SOMNIGROUP INTERNATIONAL INC.
		CENTRAL INDEX KEY:			0001206264
		STANDARD INDUSTRIAL CLASSIFICATION:	HOUSEHOLD FURNITURE [2510]
		ORGANIZATION NAME:           	04 Manufacturing
		EIN:				331022198
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		1000 TEMPUR WAY
		CITY:			LEXINGTON
		STATE:			KY
		ZIP:			40511
		BUSINESS PHONE:		800-878-8889

	MAIL ADDRESS:	
		STREET 1:		1000 TEMPUR WAY
		CITY:			LEXINGTON
		STATE:			KY
		ZIP:			40511

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	TEMPUR SEALY INTERNATIONAL, INC.
		DATE OF NAME CHANGE:	20130614

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	TEMPUR PEDIC INTERNATIONAL INC
		DATE OF NAME CHANGE:	20031202

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	TWI HOLDINGS INC
		DATE OF NAME CHANGE:	20021119
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wk-form4_1755721782.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0508</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2025-08-19</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001206264</issuerCik>
        <issuerName>SOMNIGROUP INTERNATIONAL INC.</issuerName>
        <issuerTradingSymbol>SGI</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001448352</rptOwnerCik>
            <rptOwnerName>BUSTER H CLIFFORD III</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O SOMNIGROUP NTERNATIONAL INC.</rptOwnerStreet1>
            <rptOwnerStreet2>1000 TEMPUR WAY</rptOwnerStreet2>
            <rptOwnerCity>LEXINGTON</rptOwnerCity>
            <rptOwnerState>KY</rptOwnerState>
            <rptOwnerZipCode>40511</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>CEO of Tempur Sealy</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2025-08-19</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>70134</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>81.1956</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>210621</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>289379</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Buster Family Trust</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $80.8536 to $81.7486. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote.</footnote>
        <footnote id="F2">These shares of SGI common stock are held by a family trust of which the reporting person is trustee. The reporting person's spouse is the sole beneficiary of the trust.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Bhaskar Rao Attorney-in-Fact</signatureName>
        <signatureDate>2025-08-20</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
