EXHIBIT NO. 99.16 (a)

MFS MUNICIPAL SERIES TRUST

POWER OF ATTORNEY

The undersigned, Trustees of MFS Municipal Series Trust (the “Registrant”), hereby severally constitute and appoint Heidi W. Hardin, Christopher R. Bohane, Thomas H. Connors, Brian E. Langenfeld, Amanda Mooradian, and Susan A. Pereira, and each of them singly, as true and lawful attorneys, with full power to them and each of them to sign for each of the undersigned, in the names of, and in the capacities indicated below, the Registration Statement on Form N-14 with respect to the proposed transfer of all of the assets of MFS Tennessee Municipal Bond Fund, to MFS Municipal Intermediate Fund, each a series of the Registrant, in exchange solely for the assumption of certain identified liabilities of MFS Tennessee Municipal Bond Fund and the issuance to MFS Tennessee Municipal Bond Fund of shares of beneficial interest in MFS Municipal Intermediate Fund (the “Reorganization”) and any and all amendments thereto and to file the same with all exhibits thereto, and other documents in connection therewith, with the Securities and Exchange Commission for the purpose of registering the shares issued in the Reorganization by the Registrant under the Securities Act of 1933 granting unto said attorneys, and each of them, acting alone, full power and authority to do and perform each and every act and thing requisite or necessary or desirable to be done in the premises, as fully to all intents and purposes as he or she might or could do in person, hereby ratifying and confirming all that said attorneys or any of them may lawfully do or cause to be done by virtue thereof.

IN WITNESS WHEREOF, the undersigned have hereunto set their hand on this 6^th day of May, 2021.

STEVEN E. BULLER Steven E. Buller	Trustee
JOHN A. CAROSELLI John A. Caroselli	Trustee
MAUREEN R. GOLDFARB Maureen R. Goldfarb	Trustee
PETER D. JONES Peter D. Jones	Trustee
JOHN P. KAVANAUGH John P. Kavanaugh	Trustee

JAMES W. KILMAN, JR. James W. Kilman, Jr.	Trustee
ROBERT J. MANNING Robert J. Manning	Trustee
CLARENCE OTIS, JR. Clarence Otis, Jr.	Trustee
MICHAEL W. ROBERGE Michael W. Roberge	Trustee
MARYANNE L. ROEPKE Maryanne L. Roepke	Trustee
LAURIE J. THOMSEN Laurie J. Thomsen	Trustee