<SEC-DOCUMENT>0001127602-25-013174.txt : 20250502
<SEC-HEADER>0001127602-25-013174.hdr.sgml : 20250502
<ACCEPTANCE-DATETIME>20250502161231
ACCESSION NUMBER:		0001127602-25-013174
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20250430
FILED AS OF DATE:		20250502
DATE AS OF CHANGE:		20250502

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Larson Betty D
		CENTRAL INDEX KEY:			0001617903
		ORGANIZATION NAME:           	

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-06571
		FILM NUMBER:		25908666

	MAIL ADDRESS:	
		STREET 1:		126 EAST LINCOLN AVENUE
		STREET 2:		PO BOX 2000
		CITY:			RAHWAY
		STATE:			NJ
		ZIP:			07065

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Merck & Co., Inc.
		CENTRAL INDEX KEY:			0000310158
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		ORGANIZATION NAME:           	03 Life Sciences
		EIN:				221918501
		STATE OF INCORPORATION:			NJ
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		126 EAST LINCOLN AVENUE
		STREET 2:		P.O. BOX 2000
		CITY:			RAHWAY
		STATE:			NJ
		ZIP:			07065
		BUSINESS PHONE:		908-740-4000

	MAIL ADDRESS:	
		STREET 1:		126 EAST LINCOLN AVENUE
		STREET 2:		P.O. BOX 2000
		CITY:			RAHWAY
		STATE:			NJ
		ZIP:			07065

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	Merck & Co. Inc.
		DATE OF NAME CHANGE:	20091103

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	SCHERING PLOUGH CORP
		DATE OF NAME CHANGE:	19920703
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>form4.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0508</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2025-04-30</periodOfReport>

    <issuer>
        <issuerCik>0000310158</issuerCik>
        <issuerName>Merck &amp; Co., Inc.</issuerName>
        <issuerTradingSymbol>MRK</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001617903</rptOwnerCik>
            <rptOwnerName>Larson Betty D</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>126 EAST LINCOLN AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>RAHWAY</rptOwnerCity>
            <rptOwnerState>NJ</rptOwnerState>
            <rptOwnerZipCode>07065</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isOfficer>1</isOfficer>
            <officerTitle>EVP, Chief HR Officer</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2025-04-30</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>11350</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>84.71</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>11350</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2025-04-30</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>5153</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>84.71</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>6197</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Restricted Stock Unit</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2025-04-30</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>11350</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2025-04-30</value>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <value>2027-04-30</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>11350</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>22700</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Each restricted stock unit represents a contingent right to receive one share of Merck &amp; Co., Inc. common stock.</footnote>
        <footnote id="F2">These restricted stock units vest and are distributed as shares of Merck &amp; Co., Inc. common stock in three equal installments on 4/30/2025, 4/30/2026 and 4/30/2027.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Kelly E. W. Grez as Attorney-in-Fact for Betty Larson</signatureName>
        <signatureDate>2025-05-02</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
