The Military Assistance Command, Vietnam (known as mac vee) was the United States command structure during the Vietnam War from 1962 until the war's end. It was also nicknamed Pentagon East.
MACV grew out of the earlier Military Assistance and Advisory Group (MAAG), known as MAAG Indochina, that was established in 1950 to assist the French and subsequently Republic of Vietnam (or South Vietnam).
From May 1954 to February 1962, the MACV was commanded by Samuel T. Williams, Lionel C. McGarr, and Charles J. Timmes, in succession. The most famous American general in Vietnam, General William C. Westmoreland served as commander of MACV from 1964 to 1968. He was succeeded by General Creighton Abrams.