Viet Cong were South Vietnamese guerrillas who fought South Vietnamese and United States military forces during the Vietnam War (1957-1975). The Communist government of North Vietnam supported the Viet Cong. The guerrillas sought to overthrow South Vietnam’s government and unite North and South Vietnam.
The Viet Cong began as a Vietnamese nationalist group called the Vietminh (Revolutionary League for the Independence of Vietnam). In 1946, the Vietminh began a long war against the French forces in Vietnam, which was then a colony of French Indochina. The Communist leader Ho Chi Minh headed the Vietminh.
In 1957, South Vietnamese President Ngo Dinh Diem began to crack down on Communists and other political groups in his country. Diem described anyone who resisted his rule as Viet Cong, whether they were Communists or not. The term cong is scornful slang for Communists. Diem’s actions increased opposition to his rule and drove many non-Communists into an alliance with the Communists.
In 1960, various anti-Diem groups formed the National Liberation Front (NLF). The NLF’s military wing, called the People’s Liberation Armed Forces, was labeled the Viet Cong by its opponents. With North Vietnamese backing, the Viet Cong waged a successful guerrilla war against Diem’s army. The United States, which wanted to stop the spread of Communism, responded by sending thousands of troops to South Vietnam in 1965. North Vietnam, in turn, sent thousands of its troops. In the late 1960’s, Viet Cong casualties began to mount, and North Vietnam switched its focus to conventional warfare. As a result, the Viet Cong played a lesser role in the rest of the war. In 1975, the war ended, and the two Vietnams were united under Communist rule. 
