<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2013-08-02</periodOfReport>

    <issuer>
        <issuerCik>0000861884</issuerCik>
        <issuerName>RELIANCE STEEL &amp; ALUMINUM CO</issuerName>
        <issuerTradingSymbol>RS</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001256539</rptOwnerCik>
            <rptOwnerName>MOLLINS GREGG J</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>350 SOUTH GRAND AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 5100</rptOwnerStreet2>
            <rptOwnerCity>LOS ANGELES</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>90071</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>President and COO</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2013-08-02</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>2000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>70.85</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>173327</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Held by Trustee of Mollins Family Trust</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>12352</value>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Held by Trustee of Reliance Steel &amp; Aluminum Co. Employee Stock Ownership Plan</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">The price reported represents the weighted average sale price of the shares disposed of. The actual sale prices ranged from $70.83 to $70.87. The Reporting Person has provided to the Issuer and hereby undertakes to provide upon request by the U.S. Securities and Exchange Commssion Staff or a security holder of the Issuer, full information regarding the number of shares sold at each separate price.</footnote>
        <footnote id="F2">Includes 16,000 restricted shares subject to vesting over time.</footnote>
        <footnote id="F3">The Company received the allocation for the 2012 plan year under the Reliance Steel &amp; Aluminum Co. Employee Stock Ownership Plan (&quot;ESOP&quot;) on May 30, 2013. The Reporting Person acquired 80 ESOP shares for the 2012 plan year.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Gregg J. Mollins by William A. Smith II as his Attorney-in-Fact</signatureName>
        <signatureDate>2013-08-06</signatureDate>
    </ownerSignature>
</ownershipDocument>
