Orion Energy Systems, Inc.

Debt Securities

Common Stock

Preferred Stock

Warrants

Subscription Rights

Stock Purchase Contracts

Stock Purchase Units

We may offer and sell from time to time up to $100.0 million of any combination of the securities described in this prospectus, in one or more classes or series and in amounts, at prices and on terms that we will determine at the times of the offerings

This prospectus describes the general manner in which our securities may be offered using this prospectus. We will provide specific terms of the securities, including the offering prices, in one or more supplements to this prospectus. The supplements may also add, update or change information contained in this prospectus. You should read this prospectus and any prospectus supplement relating to the specific issue of securities carefully before you invest.

We may offer the securities independently or together in any combination for sale directly to purchasers or through underwriters, dealers or agents to be designated at a future date. The supplements to this prospectus will provide the specific terms of the plan of distribution.

Our common stock is listed on the NASDAQ Capital Market under the symbol "OESX." Our executive offices are located at 2210 Woodland Drive, Manitowoc, Wisconsin 54220, and our telephone number is (920) 892-9340. The last reported sale price of the common stock on March 5, 2026 was $11.06 per share.

As of March 6, 2026, the aggregate market value of our outstanding common stock held by non-affiliates, or the public float, was $71.2 million, which was calculated based on 3,878,734 shares of our outstanding common stock held by non-affiliates and on a price per share of $18.36, the closing price of our common stock on January 29, 2026. During the 12 calendar month period ending on, and including the date of this prospectus, we sold securities with an aggregate market value of $7.0 million pursuant to General Instruction I.B.6. of Form S-3 . Pursuant to General Instruction I.B.6 of Form S-3, so long as the aggregate market value of our outstanding common stock held by non-affiliates remains below $75.0 million, in no event will we sell securities in primary offerings under this prospectus where the aggregate market value of such securities sold in such offerings exceeds one-third of the aggregate market value of the voting and non-voting common equity held by our non-affiliates in any 12-month period.