U.S. Military Assistance Command, Vietnam (MACV) was a joint-service command of the United States Department of Defense.

MACV was created on 8 February 1962, in response to the increase in United States military assistance to South Vietnam. MACV was first implemented to assist the Military Assistance Advisory Group (MAAG) Vietnam, controlling every advisory and assistance effort in Vietnam, but was reorganized on 15 May 1964 and absorbed MAAG Vietnam to its command when combat unit deployment became too large for advisory group control.: 59  MACV was disestablished on 29 March 1973 and replaced by the Defense Attaché Office (DAO), Saigon. The DAO performed many of the same roles of MACV within the restrictions imposed by the Paris Peace Accords until the Fall of Saigon.: 59 The first commanding general of MACV (COMUSMACV), General Paul D. Harkins, was also the commander of MAAG Vietnam, and after reorganization was succeeded by General William C. Westmoreland in June 1964, followed by General Creighton W. Abrams (July 1968) and General Frederick C. Weyand (June 1972).: 59