In the Vietnam War, the North Vietnamese forces launch their 1975 Spring Offensive (to 30 April 1975), which results in the final capitulation of South Vietnam.

The Vietnam War was an armed conflict in Vietnam, Laos, and Cambodia fought between North Vietnam and South Vietnam and their allies. North Vietnam was supported by the Soviet Union and China, while South Vietnam was supported by the United States and other anti-communist nations. The conflict was the second of the Indochina wars and a proxy war of the Cold War between the Soviet Union and US. The Vietnam War was one of the postcolonial wars of national liberation, a theater in the Cold War, and a civil war, with civil warfare a defining feature from the outset. Direct US military involvement escalated from 1965 until its withdrawal in 1973. The fighting spilled into the Laotian and Cambodian Civil Wars, which ended with all three countries becoming communist in 1975.

North Vietnam, officially the Democratic Republic of Vietnam, was a country in Southeast Asia from 1945 to 1976, with sovereignty fully recognized in 1954. A member of the communist Eastern Bloc, it opposed the French-supported State of Vietnam and later the Western-allied Republic of Vietnam. The DRV invaded Saigon in 1975 and ceased to exist the following year when it merged with the south to become the current Socialist Republic of Vietnam.

The 1975 spring offensive, officially known as the general offensive and uprising of spring 1975, was the final North Vietnamese campaign of the Vietnam War that led to the capitulation of South Vietnam. In December 1974, People's Army of Vietnam's (PAVN) forces crossed from their bases in Cambodia and captured Phước Long Province by January 1975. After this success, the North Vietnamese leadership increased the scope of the PAVN offensive and attacked the Central Highlands from Cambodia in March, capturing the city of Buôn Ma Thuột on 18 March. These operations were intended to be preparatory to launching a general offensive in 1976.