Exhibit 5.1

Wilson Sonsini Goodrich & Rosati

Professional Corporation

650 Page Mill Road

Palo Alto, California 94304-1050

O: 650.493.9300

F: 650.493.6811

March 23, 2023

Soleno Therapeutics, Inc.

203 Redwood Shores Pkwy, Suite 500

Redwood City, CA 94065

Re: Registration Statement on Form S-8

Ladies and Gentlemen:

We have examined the Registration Statement on Form S-8 (the “Registration Statement”) to be filed by Soleno Therapeutics, Inc., a Delaware corporation, with the Securities and Exchange Commission on or about the date hereof, in connection with the registration under the Securities Act of 1933, as amended, of 238,329 shares of Common Stock reserved for issuance pursuant to the Soleno Therapeutics, Inc. 2014 Equity Incentive Plan (the “2014 Plan”) and 500,000 shares of Common Stock reserved for issuance pursuant to the Soleno Therapeutics, Inc. 2020 Inducement Equity Incentive Plan (the “Inducement Plan”, and together with the 2014 Plan, the “Plans”), all of which shares of Common Stock are referred to herein as the “Shares”. As your legal counsel, we have examined the proceedings taken and proposed to be taken in connection with the issuance, sale and payment of consideration for the Shares to be issued under the Plans.

On the basis of the foregoing, and in reliance thereon, we are of the opinion that the Shares, when issued and sold in the manner referred to in the Plans and pursuant to the agreements that accompany the Plans, will be legally and validly issued, fully paid, and nonassessable.

We consent to the use of this opinion as an exhibit to the Registration Statement, and further consent to the use of our name wherever appearing in the Registration Statement and any amendments thereto.

Very truly yours,

/s/ Wilson Sonsini Goodrich & Rosati, P.C.

WILSON SONSINI GOODRICH & ROSATI

Professional Corporation