Mill Road Capital III SC 13D NATURAL GAS SERVICES / Mill Road Capital III ownership change

CUSIP No. 63886Q109 Page 1 of 1 Page

Exhibit 1

JOINT FILING AGREEMENT

Pursuant to Rule 13d-1(k)(1) under the Securities Exchange Act of 1934, as amended, the undersigned hereby agree, as of January 4, 2021, that only one statement containing the information required by Schedule 13D, and each amendment thereto, need be filed with respect to the ownership by each of the undersigned of shares of common stock of Natural Gas Services Group, Inc., a Colorado corporation, and such statement to which this Joint Filing Agreement is attached as Exhibit 1 is filed on behalf of each of the undersigned.

MILL ROAD CAPITAL III, L.P.
By:	Mill Road Capital III GP LLC, its General Partner
By:	/s/ Thomas E. Lynch
	Thomas E. Lynch
	Management Committee Director and Chairman
MILL ROAD CAPITAL III GP LLC
By:	/s/ Thomas E. Lynch
	Thomas E. Lynch
	Management Committee Director and Chairman
THOMAS E. LYNCH
/s/ Thomas E. Lynch
Thomas E. Lynch