Form 424B5 - Prospectus [Rule 424(b)(5)]

Filed pursuant to Rule 424(b)(5)

Registration No. 333-279348

PROSPECTUS SUPPLEMENT

(To Prospectus Supplement Dated May 20, 2024, to Prospectus Dated May 16, 2024)

GRI BIO, INC.

Up to $1,038,886

Common Stock

This prospectus supplement amends, supplements, and supersedes certain information contained in the prospectus supplement dated May 20, 2024, and its accompanying prospectus dated May 16, 2024 (collectively, the “May Prospectus”), relating to the offer and sale of our common stock, par value $0.0001 per share (the “Common Stock”) through H.C. Wainwright & Co., LLC (“Wainwright”), as sales agent, in “at the market offerings” as defined in Rule 415 promulgated under the Securities Act of 1933, as amended, pursuant to the At the Market Offering Agreement with Wainwright dated as of May 20, 2024 (the “Sales Agreement”).

As of July 19, 2024, the aggregate market value of our outstanding Common Stock held by non-affiliates (the “public float”) calculated for purposes of General Instruction I.B.6 of Form S-3, was approximately $6.0 million based on 1,024,707 shares of outstanding Common Stock as of July 19, 2024, of which 8,022 shares were held by affiliates, and a price of $5.9020 per share, which was the price at which our Common Stock was last sold on the Nasdaq Capital Market on May 22, 2024.

We have sold an aggregate of $961,272 of shares of Common Stock pursuant to General Instruction I.B.6 of Form S-3 during the prior 12-calendar month period that ends on and includes the date of this prospectus supplement.

We are filing this prospectus supplement to amend the May Prospectus to update the amount of shares we are eligible to sell pursuant to such prospectus. We are increasing the amount of shares of Common Stock we may offer and sell under the Sales Agreement to an aggregate offering price of up to $1,038,886 from time to time through Wainwright, which does not include the shares of Common Stock having an aggregate gross sales price of approximately $961,272 that were sold pursuant to the May Prospectus to date. Pursuant to General Instruction I.B.6 of Form S-3, in no event will we sell securities in a public primary offering with a value exceeding one-third of our public float in any 12-month calendar period so long as our public float remains below $75.0 million. In the event that we may sell additional amounts under the Sales Agreement, we will file another prospectus supplement prior to making such additional sales.

Our Common Stock is listed on the Nasdaq Capital Market under the symbol “GRI”. On July 18, 2024, the last reported sale price of our Common Stock on the Nasdaq Capital Market was $1.71 per share.

Investing in our securities involves a high degree of risk. You should review carefully the risks and uncertainties under the heading “Risk Factors” on page 5 of the prospectus dated May 16, 2024, on page S-7 of the prospectus filed on May 20, 2024, and the other documents that are incorporated by reference to this prospectus supplement.

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Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities, or determined if this prospectus is accurate or complete. Any representation to the contrary is a criminal offense.

H.C. Wainwright & Co.

The date of this prospectus supplement is July 19, 2024

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