The Third Indochina War was a conflict that happened in the late 1970s in the countries of Vietnam, Cambodia, and Laos. The war was between North Vietnam (backed by China and the Soviet Union) and South Vietnam (backed by the United States and South Korea). North and South Vietnam were trying to take control of Vietnam, Cambodia, and Laos. Both sides wanted to be in charge of the whole region, but only one side could win. After a long, tough fight, North Vietnam won the war in 1975 and the countries of Vietnam, Cambodia, and Laos became unified under one government.