The Kennedy administration sent Victor H. Krulak and Joseph Mendenhall on a mission to assess the progress of the Vietnam War.

John F. Kennedy's tenure as the 35th president of the United States began with his inauguration on January 20, 1961, and ended with his assassination on November 22, 1963. Kennedy, a Democrat from Massachusetts, took office following his narrow victory over Republican incumbent vice president Richard Nixon in the 1960 presidential election. He was succeeded by Vice President Lyndon B. Johnson.

Victor Harold Krulak was a decorated United States Marine Corps officer who saw action in World War II, Korea and Vietnam. Krulak, considered a visionary by fellow Marines, was the author of First to Fight: An Inside View of the U.S. Marine Corps and the father of the 31st Commandant of the Marine Corps, General Charles C. Krulak.

Joseph Abraham Mendenhall was a United States State Department official, known for his advisory work during the Kennedy administration on policy towards Vietnam and Laos. He was best known for his participation in the Krulak Mendenhall mission to South Vietnam in 1963 with General Victor Krulak. Their vastly divergent conclusions led U.S. President John F. Kennedy to ask if they had visited the same country. Mendenhall continued his work in the Indochina region after Lyndon B. Johnson assumed the presidency in wake of Kennedy's assassination.

The Krulak–Mendenhall mission was a fact-finding expedition dispatched by the Kennedy administration to South Vietnam in early September 1963. The stated purpose of the expedition was to investigate the progress of the war by the South Vietnamese regime and its US military advisers against the Viet Cong insurgency. The mission was led by Victor Krulak and Joseph Mendenhall. Krulak was a major general in the United States Marine Corps, while Mendenhall was a senior Foreign Service Officer experienced in dealing with Vietnamese affairs. Civil unrest gripped South Vietnam as Buddhist demonstrations against the religious discrimination of President Ngô Đình Diệm's Catholic regime escalated. Following the raids on Buddhist pagodas on August 21 that left a death toll ranging up to a few hundred, the US had authorized investigations into a possible coup through a cable to US Ambassador Henry Cabot Lodge Jr.