<SEC-DOCUMENT>0001739998-26-000002.txt : 20260325
<SEC-HEADER>0001739998-26-000002.hdr.sgml : 20260325
<ACCEPTANCE-DATETIME>20260325160224
ACCESSION NUMBER:		0001739998-26-000002
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20260323
FILED AS OF DATE:		20260325
DATE AS OF CHANGE:		20260325

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Sandifer Andrew D
		CENTRAL INDEX KEY:			0001739998
		ORGANIZATION NAME:           	

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-32737
		FILM NUMBER:		26792382

	MAIL ADDRESS:	
		STREET 1:		FMC CORPORATION
		STREET 2:		2929 WALNUT STREET
		CITY:			PHILADELPHIA
		STATE:			PA
		ZIP:			19104

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Koppers Holdings Inc.
		CENTRAL INDEX KEY:			0001315257
		STANDARD INDUSTRIAL CLASSIFICATION:	LUMBER & WOOD PRODUCTS (NO FURNITURE) [2400]
		ORGANIZATION NAME:           	04 Manufacturing
		EIN:				201878963
		STATE OF INCORPORATION:			PA
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		436 SEVENTH AVENUE
		CITY:			PITTSBURGH
		STATE:			PA
		ZIP:			15219
		BUSINESS PHONE:		412-227-2001

	MAIL ADDRESS:	
		STREET 1:		436 SEVENTH AVENUE
		CITY:			PITTSBURGH
		STATE:			PA
		ZIP:			15219

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	KI Holdings Inc.
		DATE OF NAME CHANGE:	20050124
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wk-form4_1774468942.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0609</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2026-03-23</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001315257</issuerCik>
        <issuerName>Koppers Holdings Inc.</issuerName>
        <issuerTradingSymbol>KOP</issuerTradingSymbol>
        <issuerForeignTradingSymbol></issuerForeignTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001739998</rptOwnerCik>
            <rptOwnerName>Sandifer Andrew D</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerNonUSAddressFlag>false</rptOwnerNonUSAddressFlag>
            <rptOwnerStreet1>436 SEVENTH AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>PITTSBURGH</rptOwnerCity>
            <rptOwnerState>PA</rptOwnerState>
            <rptOwnerZipCode>15219</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable></nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Dividend Equivalent Rights</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2026-03-23</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>50</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F2"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>50</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>84.064</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>Dividend Equivalent Rights</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F3"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2026-03-23</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>5.268</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F2"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>5.268</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>89.332</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The dividend equivalent rights (&quot;DERs&quot;) accrued with respect to additional time-based restricted stock units (&quot;RSUs&quot;) credited to the reporting person with respect to RSUs granted on May 8, 2025. Each DER is the economic equivalent of one share of Koppers Holdings Inc. common stock.</footnote>
        <footnote id="F2">Once released, the RSUs corresponding to these DERs will become payable according to the election of payment designation that was filed by the reporting person subject to the Koppers Holdings Inc. Director Deferred Compensation Plan (the &quot;Plan&quot;). Such payment will be either lump sum or in annual installments commencing on the May 31st next following the reporting person's separation from service (as defined under the Plan) or, if later, and elected by the reporting person at the time he/she first elects to defer any payment under the Plan, May 31st of the year specified by the reporting person.</footnote>
        <footnote id="F3">The DERs accrued with respect to additional RSUs credited to the reporting person with respect to deferred compensation. Each DER is the economic equivalent of one share of Koppers Holdings
Inc. common stock.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Stephanie L. Apostolou, Attorney in Fact</signatureName>
        <signatureDate>2026-03-25</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
