The Vietnam War was fought in part by the US.
The Vietnam War ( Chiến tranh Việt Nam ) , also known as the Second Indochina War , and known in Vietnam as Resistance War Against America ( Kháng chiến chống Mỹ ) or simply the American War , was a war that occurred in Vietnam , Laos , and Cambodia from 1 November 1955 to the fall of Saigon on 30 April 1975 . The North Vietnamese army was supported by the Soviet Union , China and other communist allies and the South Vietnamese army was supported by the United States , South Korea , Australia , Thailand and other anti-communist allies . U.S. involvement escalated in the early 1960s , with troop levels tripling in 1961 and again in 1962 . U.S. involvement escalated further following the 1964 Gulf of Tonkin incident , in which a U.S. destroyer clashed with North Vietnamese fast attack craft , which was followed by the Gulf of Tonkin Resolution , which gave the U.S. president authorization to increase U.S. military presence .