First Watch Restaurant (FWRG) S-3 Shelf registration

Exhibit 5.1

767 Fifth Avenue

New York, NY 10153-0119

+1 212 310 8000 tel

+1 212 310 8007 fax

November 7, 2022    

First Watch Restaurant Group, Inc.

8725 Pendery Place, Suite 201,

Bradenton, FL 34201

Ladies and Gentlemen:

We have acted as counsel to First Watch Restaurant Group, Inc., a Delaware corporation (the “Company”), in connection with the preparation and filing with the Securities and Exchange Commission (the “Commission”) of the Company’s Registration Statement on Form S-3 filed on the date hereof (as amended, the “Registration Statement”) under the Securities Act of 1933, as amended (the “Act”), relating to, in each case as described in the Registration Statement, registering (i) the issuance, offering and sale by the Company, from time to time, of up to 5,000,000 shares in the aggregate of common stock, par value $0.01 per share (the “Common Stock”), of the Company (together with any additional shares that may be registered pursuant to Rule 462(b) under the Act, the “Primary Common Stock”) and (ii) the offering and sale by one or more stockholders of the Company named in the prospectus included in the Registration Statement (the “Selling Stockholders”) from time to time of up to 41,564,784 shares of Common Stock (the “Secondary Common Stock” and, together with the Primary Common Stock, the “Shares”).

In so acting, we have examined originals or copies (certified or otherwise identified to our satisfaction) of (i) the Amended and Restated Certificate of Incorporation of the Company filed with the Secretary of State of the State of Delaware, incorporated by reference as Exhibit 3.1 to the Registration Statement; (ii) the Amended and Restated Bylaws of the Company, incorporated by reference as Exhibit 3.2 to the Registration Statement; (iii) the Registration Statement; (iv) the prospectus contained within the Registration Statement; (v) the form of the Certificate of Common Stock of the Company, incorporated by reference as Exhibit 4.1 to the Registration Statement; and (vi) such corporate records, agreements, documents and other instruments, and such certificates or comparable documents of public officials and of officers and representatives of the Company, and have made such inquiries of such officers and representatives, as we have deemed relevant and necessary as a basis for the opinion hereinafter set forth.

In such examination, we have assumed the genuineness of all signatures, the legal capacity of all natural persons, the authenticity of all documents submitted to us as originals, the conformity to original documents of all documents submitted to us as certified, conformed or photostatic copies, and the authenticity of the originals of such latter documents. As to all questions of fact material to this opinion that have not been independently established, we have relied upon certificates or comparable documents of officers and representatives of the Company.

November 7, 2022 Page 2

We have also assumed that: (i) with respect to the issuance, offering and sale of shares of Primary Common Stock by the Company, the issuance (including the execution, delivery and performance thereof) and the terms of the Primary Common Stock and the terms of any offering and sale of shares of the Primary Common Stock will have been duly authorized by the Company; (ii) the Registration Statement and any amendments or supplements thereto (including any post-effective amendments) will have become, and will remain, effective and comply with all applicable laws and no stop order suspending the Registration Statement’s effectiveness will have been issued and remain in effect, in each case, at the time the Shares are offered or issued, as contemplated by the Registration Statement; (iii) the Company has timely filed all necessary reports pursuant to the Securities and Exchange Act of 1934, which are incorporated into the Registration Statement by reference; (iv) a prospectus supplement will have been prepared and filed with the Commission describing the Shares offered thereby and will at all relevant times comply with all applicable laws; (v) all shares of Primary Common Stock will be issued, offered and sold and all shares of Secondary Common Stock will be offered and sold in compliance with applicable federal and state securities laws and in the manner stated in the Registration Statement and the appropriate prospectus supplement; (vi) in the case of the issuance, offering and sale of shares of Primary Common Stock by the Company, the Company will have received the consideration therefore specified in any applicable agreement and that the consideration for such shares of Primary Common Stock will be at least equal to the par value of such shares of Primary Common Stock; (vii) any agreement with respect to the issuance, offering or sale of any Shares will have been duly authorized and validly executed and delivered by the Company and the other party or parties thereto, including in the case of the Secondary Common Stock, the Selling Stockholders; and (viii) any Shares issuable upon conversion, exercise or exchange of any Shares being offered will be duly authorized, created and, if appropriate, reserved for issuance upon such conversion, exercise or exchange.

Based on the foregoing, and subject to the qualifications stated herein, we are of the opinion that (i) the shares of Primary Common Stock, when issued and sold as contemplated by the Registration Statement, will be validly issued, fully paid and non-assessable and (ii) the shares of Secondary Common Stock are validly issued, fully paid and non-assessable.

The opinions expressed herein are limited to the corporate laws of the State of Delaware, and we express no opinion as to the effect on the matters covered by this letter of the laws of any other jurisdiction.

We hereby consent to the filing of this letter as an exhibit to the Registration Statement and to the reference to our firm under the caption “Legal Matters” in the prospectus which is 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.

Very truly yours,

/s/ Weil, Gotshal & Manges LLP