<SEC-DOCUMENT>0000310158-25-000056.txt : 20251104
<SEC-HEADER>0000310158-25-000056.hdr.sgml : 20251104
<ACCEPTANCE-DATETIME>20251104160203
ACCESSION NUMBER:		0000310158-25-000056
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20251103
FILED AS OF DATE:		20251104
DATE AS OF CHANGE:		20251104

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Williams David Michael
		CENTRAL INDEX KEY:			0001820958
		ORGANIZATION NAME:           	

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-06571
		FILM NUMBER:		251448825

	MAIL ADDRESS:	
		STREET 1:		MERCK & CO., INC.
		STREET 2:		126 EAST LINCOLN AVENUE
		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>2025-11-03</periodOfReport>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001820958</rptOwnerCik>
            <rptOwnerName>Williams David Michael</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>MERCK &amp; CO., INC.</rptOwnerStreet1>
            <rptOwnerStreet2>126 EAST LINCOLN AVENUE</rptOwnerStreet2>
            <rptOwnerCity>RAHWAY</rptOwnerCity>
            <rptOwnerState>NJ</rptOwnerState>
            <rptOwnerZipCode>07065</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isOfficer>1</isOfficer>
            <officerTitle>EVP,Chief Info&amp;Digital Officer</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2025-11-03</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>8614</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>83.5895</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>24578.031</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <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 $83.5400 to $83.6200, inclusive. The reporting person undertakes to provide to Merck &amp; Co., Inc., any security holder of Merck &amp; Co., Inc., 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 range set forth above in this footnote.</footnote>
        <footnote id="F2">Holdings include shares acquired in dividend reinvestment transactions.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Kelly E. W. Grez as Attorney-in-Fact for David Michael Williams</signatureName>
        <signatureDate>2025-11-04</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
