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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2015-12-31</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001109448</issuerCik>
        <issuerName>ALLIANCEBERNSTEIN L.P.</issuerName>
        <issuerTradingSymbol>NONE</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001257148</rptOwnerCik>
            <rptOwnerName>AXA EQUITABLE FINANCIAL SERVICES LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1290 AVENUE OF THE AMERICAS</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10104</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Units of Limited Partnership Interest</value>
            </securityTitle>
            <transactionDate>
                <value>2015-12-31</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>10000000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>76994405</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                    <footnoteId id="F5"/>
                    <footnoteId id="F6"/>
                    <footnoteId id="F7"/>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnotes</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">On December 31, 2015, ACMC, LLC (&quot;ACMC&quot;) transferred 10,000,000 units of limited partnership interests (&quot;AB Capital Units&quot;) in AllianceBernstein L.P. (&quot;AllianceBernstein&quot;) to its sole member, AXA Equitable Life Insurance Company (&quot;AXA Equitable&quot;), which in turn immediately transferred the AB Capital Units to its sole shareholder, AXA Equitable Financial Services, LLC (&quot;AXFS&quot;). Upon receipt of these AB Capital Units, AXFS immediately transferred such AB Capital Units to its sole member, AXA Financial, Inc. (&quot;AXF&quot;).</footnote>
        <footnote id="F2">Not applicable.</footnote>
        <footnote id="F3">AXA indirectly owns (i) all of the common stock of AXA America Holdings, Inc., a holding company for a group of insurance and related financial services companies, AXF and its subsidiaries and AXA America Corporate Solutions, Inc. and its wholly owned subsidiary, Coliseum Reinsurance Company (&quot;Coliseum Reinsurance&quot;) and (ii) 96.23% of the outstanding shares of common stock of AXA-IM Holding U.S. Inc. (&quot;AXA-IM Holding&quot;), a holding company for a group of asset management companies. AXF is the sole member of AXFS which wholly owns (i) AXA Equitable which in turn owns ACMC and (ii) MONY Life Insurance Company of America (&quot;MLOA&quot;).</footnote>
        <footnote id="F4">As of December 31, 2015, AXA Assurances I.A.R.D. Mutuelle and AXA Assurances Vie Mutuelle (collectively, &quot;Mutuelles AXA&quot;), directly beneficially owned approximately 14.03% of the issued ordinary shares (representing approximately 23.61% of the voting power) of AXA. The Mutuelles AXA and AXA expressly declare that the filing of this Form 4 shall not be construed as an admission that either of them is, for purposes of Section 16 of the Securities Exchange Act of 1934, the beneficial owner of any securities covered by this Form 4.</footnote>
        <footnote id="F5">AXA has deposited its shares of common stock (&quot;Common Stock&quot;) of AXF into a voting trust. AXA will remain the indirect beneficial owner of such Common Stock, but during the term of the voting trust, the AXA Voting Trustees (Mark Pearson, Henri de Castries and Denis Duverne) will exercise all voting rights with respect to the Common Stock. By reason of the voting trust and their relationship with AXA and the Mutuelles AXA, the AXA Voting Trustees may be deemed to beneficially own the securities covered by this Form 4. The AXA Voting Trustees expressly declare that the filing of this Form 4 shall not be construed as an admission that any of them is, for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, the beneficial owner of any securities covered by this Form 4.</footnote>
        <footnote id="F6">In addition to the AB Capital Units reported in this Form 4, affiliates of the Reporting Person beneficially own additional AB Capital Units and Holding Units as follows. As of the close of business on January 1, 2016, AXF beneficially owned directly 43,032,758 AB Capital Units; ACMC beneficially owned 1,444,356 Holding Units and 74,406,933 AB Capital Units; AXA-IM Holding, 41,934,582 AB Capital Units; Coliseum Reinsurance, 8,160,000 AB Capital Units; MLOA, 2,587,472 AB Capital Units; and AllianceBernstein Corporation, a wholly-owned subsidiary of AXA Equitable, owned a 1% general partnership interest in AllianceBernstein and 100,000 units of general partnership interest in Holding.</footnote>
        <footnote id="F7">The AB Capital Units are highly illiquid, and the ability of a holder of AB Capital Units to exchange them in the future for AB Units if it so desires is substantially limited. In general, transfers of AB Capital Units will be allowed only with the written consent of both AXA Equitable and the general partner of AllianceBernstein. AXA Equitable and the general partner of AllianceBernstein have stated that they intend to refuse to consent to any transfer that is not described in the safe harbors set forth in the United States Treasury regulations.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Anders Malmstrom, Senior Executive Director and Chief Financial Officer</signatureName>
        <signatureDate>2016-01-05</signatureDate>
    </ownerSignature>
</ownershipDocument>
