Prospectus Certification by Investment Company (Form 497J)

111 Huntington Avenue, Boston, Massachusetts 02199

617-954-5000

November 2, 2026

VIA EDGAR

United States Securities and Exchange Commission

100 F Street, N.E.

Washington, D.C. 20549

Re: MFS^® Series Trust XVII (the "Trust") (File Nos. 33-37615 and 811-6174) on behalf of MFS^® International Equity Fund (the "Fund")

Ladies and Gentlemen:

Pursuant to Rule 497(j) under the Securities Act of 1933, as amended, please accept this letter on behalf of the Trust as certification that the Prospectus and the Statement of Additional Information for the Fund do not differ from those contained in Post-Effective Amendment No. 57 (the "Amendment") to the Trust's Registration Statement on Form N-1A. The Amendment was filed electronically on October 27, 2026.

Please call the undersigned at (617) 954-4384 or Reaghan Shelbourn at (617) 954-4355 with any questions you may have.

Sincerely,

/s/AMANDA S. MOORADIAN

Amanda S. Mooradian

Vice President and Senior Counsel