245 Summer Street

Fidelity® Investments

Boston, MA 02210

January 31, 2022

U.S. Securities & Exchange Commission

100 F Street, N.E.

Washington, D.C. 20549

Attention: File Room

RE: Fidelity Mt. Vernon Street Trust (the trust): File Nos. 002-79755 and 811-03583 Fidelity Flex Mid Cap Growth Fund Fidelity Growth Company Fund Fidelity Growth Company K6 Fund Fidelity Growth Strategies Fund Fidelity Growth Strategies K6 Fund Fidelity New Millennium Fund Fidelity Series Growth Company Fund (the fund(s))

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Ladies and Gentlemen:

Transmitted herewith pursuant to Rule 497(j) under the Securities Act of 1933 is certification that the Prospectus(es) and Statement(s) of Additional Information with respect to the above referenced fund(s) do not differ from those filed in the most recent post-effective amendment, which was filed electronically.

Very truly yours,

/s/Cynthia Lo Bessette

Cynthia Lo Bessette

Secretary of the Trust