The Indochina Wars (Vietnamese: Chiến tranh Đông Dương) were a series of wars which were waged in Southeast Asia from 1946 to 1991, by communist Indochinese forces (mainly the Democratic Republic of Vietnam) against anti-communist forces (mainly French, the State of Vietnam, American, Cambodian, Laotian Royal, and Chinese forces). The term "Indochina" originally referred to French Indochina, which included the current states of Vietnam, Laos, and Cambodia. In current usage, it applies largely to a geographic region, rather than to a political area. The wars included:

• The First Indochina War (called the Indochina War in France and the French War in Vietnam) began after the end of World War II in 1946 and lasted until the French defeat in 1954. After a long campaign of resistance against the French and the Japanese, Viet Minh forces had claimed a victory (the August Revolution) after Japanese and Vichy French forces surrendered in the North on 15 August 1945. In the War in Vietnam (1945–46), British forces temporarily occupied the South, starting from 13 September 1945, only to restore French colonial control in 1946. In the United Nations, and through their alliance with the United Kingdom and the United States, the French demanded return of their former Indochina colony prior to agreeing to participate in the NATO alliance (founded in 1949) opposing Soviet expansion beyond the countries of the Warsaw Pact (founded in 1955) in the Cold War. The communist/nationalist Viet Minh, whom the Allies had supported during World War II, continued fighting the French with support from China and the Soviet Union, ultimately forcing the NATO-backed French out of Indochina (1954).
• The Second Indochina War (called the Vietnam War in the West or the American War in Vietnam) began as a conflict between the United States-backed South Vietnamese government and its opponents, both the North Vietnamese-based communist Viet Cong (National Liberation Front) and the People's Army of Vietnam (PAVN), known in the West as the North Vietnamese Army (NVA). The conflict began in 1955 and lasted until 1975 when the North Vietnamese conquered South Vietnam. The United States, which had supported France during the first Indochina war, backed the Republic of Vietnam government in opposition to the communist Viet Cong and PAVN. The North benefited from military and financial support from China and the Soviet Union, members of the communist bloc. Fighting also occurred during this time in Cambodia between the US-backed government, the PAVN, and the communist-backed Khmer Rouge (known as the Cambodian Civil War, 1967–1975) and in Laos between the US-backed government, the PAVN, and the communist-backed Pathet Lao (known as the Laotian Civil War or Secret War, 1959–1975).
• The Third Indochina War was a period of prolonged conflict following the Vietnam War, in which several wars were fought:

• The Cambodian–Vietnamese War began when Vietnam invaded Cambodia and deposed the genocidal Khmer Rouge regime. The war lasted from May 1975 to December 1989.

• The Sino-Vietnamese War was a short war fought in February–March 1979 between the People's Republic of China and the Socialist Republic of Vietnam. The Chinese launched a punitive expedition in revenge for the Vietnamese invasion of Cambodia, and withdrew a month later to prewar positions. Skirmishes along the border would continue until November 1991.

• After the triumph of the Pathet Lao, an anti-communist insurgency in Laos lasted until most Hmong insurgents surrendered in 2007, though some resistance cells remained active for several years after. Thailand, which supported the Lao insurgents, as well as the anti-Vietnamese forces in the Third Indochina War, fought a few skirmishes with Vietnam in 1984, and a short conflict with Laos in 1987.

• FULRO insurgency against Vietnam - United Front for the Liberation of Oppressed Races

• The Communist Party of Thailand fought an insurgency from 1965 to 1989. They received backing from Laos and Vietnam from 1975 to 1979 but were expelled from their bases and lost most of their supply lines after they sided with the Cambodian-Chinese aligned forces, rather than the pro-Soviet Vietnamese and Laotian regimes.