WY: amended insider filing

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    <schemaVersion>X0609</schemaVersion>

    <documentType>4/A</documentType>

    <periodOfReport>2026-05-15</periodOfReport>

    <dateOfOriginalSubmission>2026-05-18</dateOfOriginalSubmission>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000106535</issuerCik>
        <issuerName>WEYERHAEUSER CO</issuerName>
        <issuerTradingSymbol>WY</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001183850</rptOwnerCik>
            <rptOwnerName>PIASECKI NICOLE WEYERHAEUSER</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerNonUSAddressFlag>false</rptOwnerNonUSAddressFlag>
            <rptOwnerStreet1>2000 WELLS FARGO PLACE</rptOwnerStreet1>
            <rptOwnerStreet2>30 EAST 7TH STREET</rptOwnerStreet2>
            <rptOwnerCity>SAINT PAUL</rptOwnerCity>
            <rptOwnerState>MN</rptOwnerState>
            <rptOwnerZipCode>55101-4930</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Share equivalents</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2026-05-15</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>7832</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F1"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>7832</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>93391.357</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
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        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The stock equivalents reported herein were acquired pursuant to the Issuer's Fee Deferral Plan for Directors. The Reporting Person elected to defer receipt of 7,832 restricted stock units into an equal number of stock equivalents. The restricted stock units (rounded down to the nearest whole unit) represent the equity portion of the annual retainer fee in the amount of $180,000, with the number of units determined by dividing the dollar amount of the fee by $22.98, the average of the high ($23.40) and low ($22.56) price of the Issuer's common stock on the date of the grant. Additional stock equivalents accrue as and when dividends are paid on the Issuer's common stock. Stock equivalents are paid in an equal number of shares of the Issuer's common stock upon the Reporting Person's termination of service as a director.</footnote>
        <footnote id="F2">Reported holdings include stock equivalents acquired since the Reporting Person's last filing on Form 4 from dividend reinvestment transactions exempt from Section 16 of the Securities Exchange Act of 1934, as amended.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Jason K Mitchell, Attorney-in-fact for Nicole W. Piasecki</signatureName>
        <signatureDate>2026-05-19</signatureDate>
    </ownerSignature>
</ownershipDocument>