Prospectus by Investment Company (Form 497)

MASSMUTUAL FUNDS
MassMutual Mid Cap Value Fund
(the "Fund")
Supplement dated July 1, 2022 to the
Prospectus dated February 1, 2022 and the
Summary Prospectus dated February 1, 2022

This supplement provides new and additional information beyond that contained in the Prospectus and Summary Prospectus, and any previous supplements. It should be retained and read in conjunction with the Prospectus and Summary Prospectus, and any previous supplements.

Effective December 31, 2022, the information for Phillip N. Davidson found under the heading Portfolio Manager(s) in the section titledManagement(page 67 of the Prospectus) as well as under the headingSubadvisers and Portfolio Managersin the section titled Management of the Funds on page 139 of the Prospectus, is hereby removed due to his pending retirement from American Century Investment Management, Inc.

PLEASE RETAIN THIS SUPPLEMENT FOR FUTURE REFERENCE

B3001M-22-13
MCV-22-01​

MASSMUTUAL FUNDS
MassMutual Mid Cap Value Fund
(the "Fund")
Supplement dated July 1, 2022 to the
Statement of Additional Information dated February 1, 2022

This supplement provides new and additional information beyond that contained in the Statement of Additional Information ("SAI") and any previous supplements. It should be retained and read in conjunction with the SAI and any previous supplements.

Effective December 31, 2022, the information for Phillip N. Davidson found on page B-322 in the section titledAppendix C-Additional Portfolio Manager Informationis hereby removed due to his pending retirement fromAmerican Century Investment Management, Inc.

PLEASE RETAIN THIS SUPPLEMENT FOR FUTURE REFERENCE

SAI B3001M-22-05​