Exhibit 5.1

May 12, 2026

Kopin Corporation

125 North Drive

Westborough, MA 01581

Re: Post-Effective Amendment No. 1 to Registration Statement on Form S-1

Ladies and Gentlemen:

We have acted as counsel to Kopin Corporation (the “Company”) in connection with the filing of the Post-Effective Amendment No. 1 to the Registration Statement on Form S-1 (File No. 333-291345) originally filed by the Company with the Securities and Exchange Commission (the “Commission”) under the Securities Act of 1933, as amended (the “Securities Act”) on November 7, 2026 and declared effective by the Commission on December 8, 2025 (as amended, the “Registration Statement”). The Registration Statement relates to the resale from time to time by selling stockholders named in the Registration Statement of up to 15,789,576 shares of the Company’s common stock, par value $0.01 per share (the “Shares”).

In connection with this opinion letter, we have examined the Registration Statement and originals, or copies certified or otherwise identified to our satisfaction, of the Amended and Restated Certificate of Incorporation, as amended through the date hereof, and the Sixth Amended and Restated Bylaws, as in effect on the date hereof, of the Company and such other documents, records and other instruments as we have deemed appropriate for purposes of the opinion set forth herein.

We have assumed the genuineness of all signatures, the legal capacity of all natural persons, the authenticity of the documents submitted to us as originals, the conformity with the originals of all documents submitted to us as certified, facsimile or photostatic copies and the authenticity of the originals of all documents submitted to us as copies.

Based upon the foregoing and subject to the qualifications and assumptions stated herein, we are of the opinion that the Shares are validly issued, fully paid and non-assessable.

We hereby consent to the use of this opinion as Exhibit 5.1 to the Registration Statement and to the reference to us under the caption “Legal Matters” in the prospectus included in the Registration Statement. In giving such consent, we do not hereby admit that we are acting within the category of persons whose consent is required under Section 7 of the Securities Act or the rules or regulations of the SEC thereunder.

Very truly yours,

/s/ Morgan, Lewis & Bockius LLP