The Vietnam War was a conflict in Vietnam, Laos, and Cambodia from 1 November 1955 to the fall of Saigon on 30 April 1975. It was nominally fought between North Vietnam and South Vietnam. North Vietnam was supported by the Soviet Union, China, and other communist allies; South Vietnam was supported by the United States, South Korea, the Philippines, Australia, Thailand, and other anti-communist allies. The war, considered a Cold War-era proxy war by some, lasted almost 20 years, with direct U.S. involvement ending in 1973, and included the Laotian Civil War and the Cambodian Civil War, which ended with all three countries becoming communist states in 1975.
The conflict emerged from the First Indochina War between the French colonial government and a left-wing revolutionary movement, the Viet Minh. After the French military withdrawal from Indochina in 1954, the US assumed financial and military support for the South Vietnamese state. The Việt Cộng, also known as Front national de libération du Sud-Viêt Nam or NLF, a South Vietnamese common front under the direction of North Vietnam, initiated a guerrilla war in the south.