Third Indochina War
Part of the Indochina Wars, the Cold War, and the Sino-Soviet split
Date1 May 1975 – 23 October 1991
(16 years, 5 months, 3 weeks and 1 day)

Vietnamese victory


Democratic Kampuchea

Lao royalists
Hmong insurgents

Supported by:
 United Kingdom
 United States

 People's Republic of Kampuchea (until 1989)
 State of Cambodia (from 1989)

Supported by:
 Soviet Union

Communist Party of Thailand

  • Pak Mai
Supported by:
Malayan Communist Party
Commanders and leaders
~800,000 military ~430,000 military Unknown
Casualties and losses
~310,000 military deaths Vietnam:
105,627 military deaths[2]

The Third Indochina War was a series of interconnected armed conflicts, mainly among the various communist factions over strategic influence in Indochina after Communist victory in South Vietnam, Laos, and Cambodia in 1975.[3] The conflict primarily started due to continued raids and incursions by the Khmer Rouge into Vietnamese territory that they sought to retake. These incursions would result in the Cambodian–Vietnamese War in which the newly unified Vietnam overthrew the Pol Pot regime and the Khmer Rouge, in turn ending the Cambodian genocide. Vietnam had installed a government led by many opponents of Pol Pot, most notably Hun Sen, a former Khmer Rouge commander. This led to Vietnam's occupation of Cambodia for over a decade. The Vietnamese push to completely destroy the Khmer Rouge led to them conducting border raids in Thailand against those who had provided sanctuary.[4][5]

China strongly objected to the invasion of Cambodia. Chinese armed forces launched a punitive operation (Sino-Vietnamese War) in February 1979 and attacked Vietnam's northern provinces, determined to contain Soviet/Vietnamese influence and prevent territorial gains in the region.[6][7]

In order to acquire full control over Cambodia the People's Army of Vietnam needed to dislodge the remaining Khmer Rouge leaders and units, which had retreated to the remote areas along the Thai-Cambodian border.[8] After the Paris Peace Conference in 1989, the PAVN withdrew from Cambodian territory. Finally regular troop engagements in the region ended after the conclusion of the 1991 Paris Peace Accords.[9][10]

In Laos, an insurgency is still ongoing, though to a lesser extent since 2007, with the government being supported by both China and Vietnam.


Soviet-Chinese discord

Main articles: Vietnam War and Sino-Soviet split

After Joseph Stalin's death in 1953,[11] Nikita Khrushchev became leader of the Soviet Union. His denouncement of Stalin and his purges, the introduction of more moderate communist policies and foreign policy of peaceful coexistence with the West angered China's leadership. Mao Zedong had been following a strict Stalinistic course, that insisted on the cult of personality as a unifying force of the nation.[12] Disagreements over technical assistance for developing China's nuclear weapons and basic economic policies further alienated the Soviets and the Chinese as opposing forces of communist influence across the globe. As decolonization movements began to pick up speed in the 1960s and many such countries descended into violence, both of the communist powers competed for political control of the various nations or competing factions in ongoing civil war fights.[13] Ever more diverging Chinese and Soviet strategic and political doctrines had increased the Sino-Soviet split of the mid-1950s.

Political developments during the Vietnam War

The Democratic Republic of Vietnam (North Vietnam), which had chosen to ally with the USSR, justified incursions into neighbouring Laos and Cambodia during the Second Indochinese War by reference to the international nature of communist revolution, where "Indochina is a single strategic unit, a single battlefield" and the Vietnam People's Army's pivotal role in bringing this about.[14] However, this internationalism was obstructed by complicated regional historical realities, such as the "timeless oppositions between the Chinese and the Vietnamese on the one hand and the Vietnamese and the Khmers on the other".[15] North Vietnam intervened in the civil war between the Royal Lao Army and the communist Pathet Lao until the establishment of the Lao People's Democratic Republic and the "Treaty of Friendship and Cooperation" signed in July 1977. Permanently stationed North Vietnamese troops secured and maintained vital supply routes and strategic staging sites (Ho Chi Minh trail).[14] From 1958 on, Northern and Southern Vietnamese combat troops also began to infiltrate the remote jungles of eastern Cambodia where they continued the Ho Chi Minh trail. The Cambodian communist insurgents had joined these sanctuaries during the late 1960s. Although co-operation took place, the Khmer communists did not adopt modern socialist doctrines and eventually allied with China.[16][17]

The complete American withdrawal instantaneously eliminated the principal and common adversary of all the communist powers.[18] The communist regimes of Cambodia, Vietnam and Laos pledged allegiance with one of these two opposing factions.

Cambodian-Vietnamese war

Main article: Khmer Rouge–Vietnamese War

The Khmer Rouge killed between 1.6 and 1.8 million Cambodians during the Cambodian Genocide. The Khmer Rouge also invaded Ba Chúc, Vietnam and massacred 3,157 Vietnamese civilians, which prompted Vietnam to invade Cambodia and overthrow the regime.

After the Fall of Saigon and Phnom Penh in April and May 1975 and the subsequent communist takeover in Laos five months later, Indochina was dominated by communist regimes. Armed border clashes between Cambodia and Vietnam soon flared up and escalated as Khmer Rouge forces advanced deep into Vietnamese territory and raided villages, killing hundreds of civilians. Vietnam counterattacked and in December 1978, NVA troops invaded Cambodia, reaching Phnom Penh in January 1979 and arriving at the Thai border in spring 1979.[19][3]

However, as China, the U.S. and the majority of the international community opposed the Vietnamese campaign, the remaining Khmer Rouge managed to permanently settle in the Thai-Cambodian border region. In a United Nations Security Council meeting, seven non-aligned members drafted a resolution for a ceasefire and Vietnamese withdrawal which failed due to opposition from the Soviet Union and Czechoslovakia. Thailand tolerated the presence of the Khmer Rouge on its soil as they helped to contain the Vietnamese and Thai domestic guerillas. Over the course of the following decade, the Khmer Rouge received considerable support from Vietnam's enemies and served as a bargaining tool in the Realpolitik of Thailand, China, the ASEAN and the U.S.[20][9]

Vietnamese-Thailand conflict

Main article: Vietnamese border raids in Thailand

Khmer Rouge forces operated from inside Thai territory attacking the pro-Hanoi People's Republic of Kampuchea's government. Similarly Vietnamese forces frequently attacked the Khmer Rouge bases inside Thailand. Eventually Thai and Vietnamese regular troops clashed on several occasions during the following decade.[21] The situation escalated as Thailand's territorial sovereignty was violated on numerous occasions. Heavy fighting with many casualties resulted from direct confrontations between Vietnamese and Thai troops. Thailand increased troop strength, purchased new equipment and built a diplomatic front against Vietnam.[18]

Sino-Vietnamese conflicts

Main articles: Sino-Vietnamese War and Sino-Vietnamese conflicts, 1979–1991

China attacked Vietnam in response to Vietnam's occupation of Cambodia, entered northern Vietnam and captured several cities near the border. On March 6, 1979, China declared that their punitive mission had been successful and withdrew from Vietnam. However, both China and Vietnam claimed victory. The fact that Vietnamese forces continued to stay in Cambodia for another decade implies that China's campaign was a strategic failure. On the other hand, the conflict had proven that China had succeeded in preventing effective Soviet support for its Vietnamese ally.[22][23]

As forces remained mobilized, the Vietnamese Army and the Chinese People's Liberation Army engaged in another decade-long series of border disputes and naval clashes that lasted until 1990. These mostly local engagements usually wore out in prolonged stand-offs, as neither side achieved any long-term military gains. By the late 1980s the Vietnamese Communist Party's (VCP) began to adopt its Doi Moi (renovation) policy and reconsider its China policy in particular. Prolonged hostile relations with China had been recognized as to be detrimental to economic reforms, national security and the regime's survival. A number of political concessions opened the way for the normalization process of 1991.[24]

Regional conflicts

See also



  1. ^ "Outside Interference in Vietnamese Affairs Condemned" (PDF). July 20, 1978.
  2. ^ Chuyên đề 4 CÔNG TÁC TÌM KIẾM, QUY TẬP HÀI CỐT LIỆT SĨ TỪ NAY ĐẾN NĂM 2020 VÀ NHỮNG NĂM TIẾP THEO,ản%20lý%20chỉ%20đạo/Chuyên%20đề%204.doc
  3. ^ a b "Vietnam War - Facts, information and articles about The Vietnam War". HistoryNet. Retrieved March 31, 2018.
  4. ^ Kelvin Rowley. "Second Life, Second Death: The Khmer Rouge After 1978" (PDF). Swinburne University of Technology. Archived from the original (PDF) on February 16, 2016. Retrieved March 11, 2018.
  5. ^ "1978-1979 - Vietnamese Invasion of Cambodia". GlobalSecurity. Retrieved March 11, 2018.
  6. ^ Bernard K. Gordon (September 1986). "The Third Indochina Conflict". Foreign Affairs. 65 (Fall 1986). Retrieved March 11, 2018.
  7. ^ "The 1979 campaign" (PDF). All Partners Access Network. Archived from the original (PDF) on July 6, 2020. Retrieved March 31, 2018.
  8. ^ "Viets shell Cambodian positions..." January 2, 1985. Retrieved March 11, 2018.
  9. ^ a b Lucy Keller. "UNTAC in Cambodia – from Occupation, Civil War and Genocide to Peace - The Paris Peace Conference in 1989" (PDF). Max-Planck-Institut für ausländisches öffentliches Recht und Völkerrecht. Retrieved March 31, 2018.
  10. ^ "Cambodia - 20 years on from the Paris Peace Agreements". OHCHR. October 21, 2011. Retrieved March 31, 2018.
  11. ^ "Joseph Stalin dies - Mar 05, 1953". Retrieved April 24, 2017.
  12. ^ Clines, Francis X. (April 6, 1989). "Soviets, After 33 Years, Publish Khrushchev's Anti-Stalin Speech". The New York Times. Retrieved February 29, 2016.
  13. ^ Harry Powell. "Chinese Communist Critiques of Soviet Society". Encyclopedia of Anti-Revisionism. Retrieved March 11, 2018.
  14. ^ a b Carlyle A. Thayer. "SECURITY ISSUES IN SOUTHEAST ASIA: THE THIRD INDOCHINA WAR". SCRIBD. Retrieved March 31, 2018.
  15. ^ Christopher E. Goscha. "Vietnam, the Third Indochina War and the meltdown of Asian internationalism, p. 161" (PDF). UQAM - Université du Québec à Montréal. Retrieved March 31, 2018.
  16. ^ William S. Turley (October 17, 2008). The Second Indochina War: A Concise Political and Military History. Rowman & Littlefield Publishers. ISBN 9780742557451. Retrieved March 31, 2018.
  17. ^ "America's Vietnam War in Indochina War in Cambodia". US History. Retrieved March 31, 2018.
  18. ^ a b William S. Turley, Jeffrey Race (1980). "The Third Indochina War". Foreign Policy (38): 92–116. doi:10.2307/1148297. JSTOR 1148297. S2CID 158492536.
  19. ^ Kevin Doyle (September 14, 2014). "Vietnam's forgotten Cambodian war". BBC News. BBC. Retrieved March 31, 2018.
  20. ^ Ted Galen Carpenter. "U.S. Aid to Anti-Communist Rebels: The "Reagan Doctrine" and Its Pitfalls" (PDF). Cato Institute. Retrieved March 31, 2018.
  21. ^ "Vietnam, Thai clash continues". Star News. June 25, 1980. Archived from the original on March 8, 2021. Retrieved March 31, 2018.
  22. ^ "The Third Indochina War". Global Security. Retrieved March 11, 2018.
  23. ^ Elleman, Bruce A. (2001). Modern Chinese Warfare, 1795-1989. Routledge. p. 297. ISBN 978-0415214742.
  24. ^ Le Hong Hiep (June 26, 2013). "Vietnam's Domestic–Foreign Policy Nexus: Doi Moi, Foreign Policy Reform, and Sino Vietnamese Normalization". Asian Politics & Policy. 5 (3): 387–406. doi:10.1111/aspp.12035.