EX-5.1

Exhibit 5.1

SPIRE INC.

700 Market Street

St. Louis, MO 63101

Mark C. Darrell

Senior Vice President,

Chief Legal and Compliance Officer

June 16, 2023

Spire Inc.

700 Market Street

St. Louis, Missouri 63101

Re: Registration Statement on Form S-3

File No. 333-264799

Ladies and Gentlemen:

I am Senior Vice President, Chief Legal and Compliance Officer of Spire Inc., a Missouri corporation (the “Company”), and have served in that capacity in connection with the registration, pursuant to a Registration Statement on Form S-3 (File No. 333-264799) (the “Registration Statement”), which included a prospectus dated May 9, 2022, as supplemented by the prospectus supplement dated May 9, 2022 (the “Prospectus Supplement”) and the pricing supplement dated June 13, 2023 to the Prospectus Supplement (the “Pricing Supplement”), filed with the Securities and Exchange Commission (the “Commission”) under the Securities Act of 1933, as amended (the “Act”), of the offering and sale by the Company of 2,006,231 (the “Shares”) of the Company’s common stock, par value $1.00 per share (“Common Stock”), pursuant to the terms of (A) an equity distribution agreement, dated February 6, 2019, as modified by letter agreements dated May 14, 2019 and May 9, 2022 (the “Distribution Agreement”), by and among the Company and RBC Capital Markets, LLC, BofA Securities, Inc., Morgan Stanley & Co. LLC and TD Securities (USA) LLC, as sales agents, and Royal Bank of Canada, Bank of America, N.A., Morgan Stanley & Co. LLC and The Toronto-Dominion Bank, as forward purchasers and (B) a terms agreement, dated June 13, 2023 (the “Terms Agreement” and together with the Distribution Agreement, the “Transaction Agreements”), by and between the Company and Morgan Stanley & Co. LLC, as underwriter, forward purchaser and forward seller. This opinion is being furnished in accordance with the requirements of Item 601(b)(5) of Regulation S-K under the Act.

I have reviewed the Registration Statement and the Transaction Agreements. In addition, I have examined originals or certified copies of the resolutions adopted by the Board of Directors of the Company (the “Board”) authorizing the issuance and sale of the Shares (the “Resolutions”) and such other corporate records of the Company and other certificates and documents of officials of the Company, public officials and others as I have deemed appropriate for purposes of this letter. I have assumed the genuineness of all signatures, the legal capacity of all natural persons, the authenticity of all documents submitted to me as originals and the conformity to authentic original documents of all copies submitted to me as conformed, certified or reproduced copies.

As to various questions of fact relevant to this letter, I have relied, without independent investigation, upon certificates of public officials and certificates of officers of the Company, all of which I assume to be true, correct and complete.

Based upon the foregoing, and subject to the assumptions, exceptions, qualifications and limitations set forth herein, I am of the opinion that when any of the Shares have been issued and delivered against payment in full of the consideration payable therefor as contemplated by the Transaction Agreements, such Shares will be duly authorized and validly issued and will be fully paid and non-assessable. The opinions and other matters in this letter are qualified in their entirety and subject to the following:

I express no opinion as to the laws of any jurisdiction other than the laws of the State of Missouri.