EXHIBIT A JOINT FILING AGREEMENT

EXHIBIT A

JOINT FILING AGREEMENT

This will confirm the agreement by and among the undersigned that the Schedule 13G filed with the Securities and Exchange Commission on or about the date hereof with respect to the beneficial ownership by the undersigned of the shares of Common Stock, par value $0.01 per share, of LifeStance Health Group, Inc. (this “Agreement”), is being filed, and all amendments thereto will be filed, on behalf of each of the persons and entities named below that is named as a reporting person in such filing in accordance with Rule 13d-1(k) under the Securities Exchange Act of 1934, as amended. This Agreement may be executed in two or more counterparts, each of which shall be deemed an original, but all of which together shall constitute one and the same instrument.

Dated:    February 4, 2022

		Summit Partners, L.P.
		By:		Summit Master Company, LLC
		Its:		General Partner
		By:		*
				Authorized Signatory
		Summit Partners Growth Equity Fund IX-A, L.P.
		By:		Summit Partners GE IX, LP
		Its:		General Partner
		By:		*
				Authorized Signatory
		Summit Partners Growth Equity Fund IX-B, L.P.
		By:		Summit Partners GE IX, LP
		Its:		General Partner
		By:		*
				Authorized Signatory
		Summit Investors GE IX/XX XX, LLC
		By:		Summit Investors Management, LLC
		Its:		Manager
		By:		*
				Authorized Signatory

		Summit Investors GE IX/XX XX (UK), L.P.
		By:		Summit Investors Management, LLC
		Its:		Manager
		By:		*
				Authorized Signatory
		Summit Partners Entrepreneur Advisors Fund II, L.P.
		By:		Summit Partners Entrepreneur Advisors XX XX, LLC
		Its:		General Partner
		By:		*
				Name:
				Title: Authorized Signatory
*		By:		/s/ Xxxx X. Xxxxxxxxx
				Xxxx X. Xxxxxxxxx
				Power of Attorney**

** Pursuant to Powers of Attorney attached hereto as Exhibit B.