Peter M. Murphy is an American lawyer, and former senior legal advisor to the Commandant of the Marine Corps.

United States Secretary of Defense asked Murphy to serve on a panel to look into the Haditha incident in 2006.

[9][10] The Marine Corps flag from behind his desk was taken and memorialised, being flown in Afghanistan, before being sent into outer space.

[11] He is notable for his participation in discussions, in December 2002, of reports that interrogators from the Joint Task Force 160 and Joint Task Force 170 were using controversial interrogation techniques on the captives held in the Guantanamo Bay detention camps, in Cuba.

[1] Murphy was the Counsel to the Commandant of the United States Marine Corps's when Alberto J. Mora, the Department of the Navy's General Counsel convened several meetings of the Navy's most senior lawyers after David Brant, the Director of the NCIS, drew Mora's attention to use of the questionable interrogation techniques by the Navy's tenants at Guantanamo.