Joseph A. Mendenhall (born January 15, 1920) was U.S. State Department official, known for his advisory work during the Kennedy administration on policy towards Vietnam and Laos. He is 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.