Vice Admiral Mark Irby "MRT" Fox, USN (born March 1, 1956) is a United States Navy officer currently serving as the Deputy Commander of United States Central Command. Prior to assuming his duties at CENTCOM, he served as Deputy Chief of Naval Operations for Operations, Plans, and Strategy (N3/N5), Commander, U.S. Naval Forces Central Command (COMUSNAVCENT) and Commander, U.S. 5th Fleet (COMFIFTHFLT). He also previously served as the Commander of the Naval Strike and Air Warfare Center (NSAWC) at Naval Air Station Fallon, Nevada, and as Communications Division Chief, American Embassy Annex, Baghdad, Iraq.