EX-5.1

Exhibit 5.1

910 LOUISIANA STREET
HOUSTON, TEXAS
77002-4995

TEL +1 713.229.1234

FAX +1 713.229.1522

BakerBotts.com

AUSTIN

BRUSSELS

DALLAS

DUBAI

HOUSTON

LONDON

NEW YORK

PALO ALTO

RIYADH

SAN FRANCISCO

SINGAPORE

WASHINGTON

October 31, 2025

Westlake Corporation

2801 Post Oak Boulevard, Suite 600

Houston, Texas 77056

Ladies and Gentlemen:

As set forth in the Registration Statement on Form S-3 (the “Registration Statement”) to be filed on the date hereof by Westlake Corporation, a Delaware corporation (the “Company”), with the Securities and Exchange Commission (the “Commission”) under the Securities Act of 1933, as amended (the “Act”), relating to the offering of securities that may be issued and sold by the Company, and up to 4,500,000 currently outstanding shares of common stock, par value $0.01 per share, of the Company (the “Common Stock”) that may be sold by the selling stockholder identified in the Registration Statement (the “Selling Stockholder”), from time to time pursuant to Rule 415 under the Act, certain legal matters in connection with such securities are being passed upon for the Company by us. Such securities include (i) unsecured debt securities of the Company (the “Debt Securities”), (ii) shares of preferred stock, par value $0.01 per share, of the Company (the “Preferred Stock”), (iii) shares of Common Stock and (iv) warrants to purchase any combination of Debt Securities, Common Stock, Preferred Stock and other securities (the “Warrants”). The Debt Securities, the Preferred Stock, the Common Stock and the Warrants are collectively referred to herein as the “Securities.” At your request, this opinion letter is being furnished to you for filing as Exhibit 5.1 to the Registration Statement.

Each series of Debt Securities will be issued pursuant to an indenture dated as of January 1, 2006, as amended or supplemented from time to time, among the Company, as issuer, the potential subsidiary guarantors named therein, and The Bank of New York Mellon Trust Company, N.A. (as successor to JPMorgan Chase Bank, National Association), as trustee (the “Indenture”). The Indenture will be supplemented, in connection with the issuance of each such series of Debt Securities, by a supplemental indenture, officers’ certificate or other writing thereunder (each, a “Supplemental Indenture”) establishing the form and terms of such series of Debt Securities.

In our capacity as your counsel in the connection referred to above, we have examined originals, or copies certified or otherwise identified, of (i) the Restated Certificate of Incorporation and the Second Amended and Restated Bylaws of the Company, each as amended to date (together, the “Charter Documents”), (ii) the Indenture, (iii) the corporate records of the Company, including minute books of the Company, as furnished to us by the Company, (iv) the Registration Statement, including the prospectus contained therein relating to the Securities, (v) certificates of public officials and of officers and other representatives of the Company and (vi) statutes and other instruments and documents as a basis for the opinions hereinafter expressed. In giving such opinions, we have relied, to the extent we deem proper, without independent investigation or verification, upon certificates, statements and other representations of officers of the Company and of governmental and public officials with respect to the accuracy of the material factual matters contained therein or covered thereby. In giving the opinions below, we have assumed, without independent investigation, that the signatures on all documents examined by us are genuine, that all documents submitted to us as originals are accurate and complete, that all documents submitted to us as copies are true, complete and correct copies of the originals thereof and that all information submitted to us was accurate and complete. In connection with this opinion letter, we have also assumed that:

(i)

the Registration Statement and any amendments thereto (including post-effective amendments) will have become effective under the Act;

(ii)

a prospectus supplement will have been prepared and filed with the Commission describing the Securities offered thereby;

(iii)

all Securities will be offered, issued and sold in compliance with applicable federal and state securities laws and in the manner stated in the Registration Statement and the applicable prospectus supplement;

(iv)

the Board of Directors of the Company or a duly constituted and acting committee thereof (such Board of Directors or committee being hereinafter referred to as the “Board”) will have taken all necessary corporate action to authorize the issuance of the Securities and any other Securities issuable on the conversion, exchange, redemption or exercise thereof, and to authorize the terms of the offering and sale of such Securities and related matters;

(v)

a definitive purchase agreement, underwriting agreement, warrant agreement or similar agreement with respect to any Securities offered will have been duly authorized and validly executed and delivered by the Company, the Selling Stockholder, if applicable, and the other parties thereto (the “Purchase Agreement”);

(vi)

any securities issuable upon conversion, exchange, redemption or exercise of any Securities being offered will be duly authorized, created and, if appropriate, reserved for issuance upon such conversion, exchange, redemption or exercise;

(vii)

all Securities, and any certificates in respect thereof, will be delivered either (a) in accordance with the provisions of the applicable Purchase Agreement approved by the Board upon payment of the consideration therefor provided for therein or (b) upon conversion, exchange, redemption or exercise of any other Security, in accordance with the terms of such Security or the instrument governing such Security providing for such conversion, exchange, redemption or exercise as approved by the Board, for the consideration approved by the Board, if any;

(viii)

in the case of shares of Common Stock or Preferred Stock to be issued by the Company, (a) certificates representing such shares will have been duly executed, countersigned, registered and delivered, or if uncertificated, valid book-entry notations will have been made in the share register of the Company, in each case in accordance with the provisions of the Charter Documents; (b) there will be sufficient shares of Common Stock or Preferred Stock authorized under the Charter Documents and not otherwise issued or reserved for issuance; and (c) the purchase price therefor payable to the Company, or, if such shares are issuable on the conversion, exchange, redemption or exercise of another Security, the consideration payable to the Company for such conversion, exchange, redemption or exercise will not be less than the par value of such shares;

(ix)

in the case of shares of Preferred Stock of any series, the Board will have taken all necessary corporate action to designate and establish the terms of such series and to approve the issuance thereof and the terms of the offering and related matters, and will have caused a certificate of designations with respect to such series to be prepared, adopted and filed with the Secretary of State of the State of Delaware;

(x)

in the case of Warrants, (a) the Board will have taken all necessary corporate action to authorize the creation of and the terms of such Warrants and the issuance of the Securities to be issued pursuant thereto and to approve the warrant agreement relating thereto; (b) such Warrants and such warrant agreement will be governed by the laws of the State of New York; (c) such warrant agreement will have been duly executed and delivered by the Company and the warrant agent thereunder appointed by the Company; (d) such warrant agreement will be the valid and legally binding obligation of the warrant agent, enforceable against such party in accordance with its terms; and (e) such Warrants or certificates representing such Warrants will have been duly executed, countersigned, registered and delivered in accordance with the provisions of such warrant agreement and the applicable Purchase Agreement to the purchasers thereof upon payment of the consideration therefor provided for therein; and

(xi)

in the case of Debt Securities of any series issuable under the Indenture:

(a)

the Board will have taken all necessary corporate action to designate and establish the terms of such series of Debt Securities in accordance with the terms of the Indenture, including, if applicable, the execution and delivery of a Supplemental Indenture by the Company and the trustee thereunder, and such series of Debt Securities will be governed by New York law and will not include any provision that is unenforceable;

(b)

the Indenture will have become qualified under the Trust Indenture Act of 1939, as amended; and

(c)

forms of Debt Securities complying with the terms of the Indenture and evidencing such Debt Securities will have been duly executed, authenticated, issued and delivered in accordance with the provisions of the Indenture.

On the basis of the foregoing, and subject to the assumptions, limitations and qualifications set forth herein, we are of the opinion that:

The shares of Common Stock and Preferred Stock that may be issued by the Company included in the Securities will, when issued, have been duly authorized by all necessary corporate actions on the part of the Company and validly issued and will be fully paid and non-assessable. With respect to the shares of Common Stock that may be sold by the Selling Stockholder, such shares of Common Stock are validly issued, fully paid and non-assessable.

The Debt Securities will, when issued, constitute legal, valid and binding obligations of the Company, enforceable against the Company in accordance with their respective terms, except to the extent that the enforceability thereof may be limited by (i) any applicable bankruptcy, insolvency, reorganization, moratorium, fraudulent transfer or conveyance or other laws relating to or affecting creditors’ rights generally, (ii) general principles of equity (regardless of whether such enforceability is considered in a proceeding in equity or at law) and (iii) any implied covenants of good faith or fair dealing.

The Warrants included in the Securities will, when issued, have been duly authorized by all necessary corporate actions on the part of the Company and validly issued and constitute legal, valid and binding obligations of the Company, enforceable against the Company in accordance with their terms, except to the extent that the enforceability thereof may be limited by (i) any applicable bankruptcy, insolvency, reorganization, moratorium, fraudulent transfer or conveyance or other laws relating to or affecting creditors’ rights generally, (ii) general principles of equity (regardless of whether such enforceability is considered in a proceeding in equity or at law) and (iii) any implied covenants of good faith or fair dealing.

The opinions set forth above in this opinion letter are limited in all respects to matters of the contract law of the State of New York, the General Corporation Law of the State of Delaware and applicable federal law, in each case, as in effect on the date hereof. We hereby consent to the filing of this opinion letter with the Commission as Exhibit 5.1 to the Registration Statement. We also consent to the reference to our Firm under the heading “Legal Matters” in the prospectus forming a part of the Registration Statement. In giving such consent, we do not hereby admit that we are in the category of persons whose consent is required under Section 7 of the Act or the rules and regulations of the Commission thereunder.

Very truly yours,

/s/ Baker Botts L.L.P.