Vietnam's 1978 invasion ended the Khmer Rouge genocide and began an eleven-year occupation that reshaped Cambodian politics and Cold War alignments in Southeast Asia.
Key Facts
- War duration
- December 1978 – September 1989
- Vietnamese invasion launched
- 25 December 1978
- Cambodian genocide deaths
- 1.2–2.8 million people
- Ba Chúc massacre victims
- Over 3,000 Vietnamese civilians
- Vietnamese withdrawal completed
- September 1989
- Paris Peace Agreements signed
- 1991
By the Numbers
Location
Cause → Event → Consequence
After both Vietnam and the Khmer Rouge defeated their respective anti-communist enemies in the Vietnam War, their alliance collapsed. The Khmer Rouge regime under Pol Pot repeatedly raided Vietnamese border provinces, culminating in massacres such as Ba Chúc in April 1978 and a full cross-border assault in December 1978, prompting Vietnam to act.
On 25 December 1978, Vietnam launched a full-scale invasion of Democratic Kampuchea, overrunning the country in roughly two weeks, capturing Phnom Penh, and ousting the Khmer Rouge government. A pro-Vietnamese communist state replaced it, while Khmer Rouge remnants retreated to jungle areas near the Thai border and continued armed resistance alongside other factions until Vietnam's complete military withdrawal in September 1989.
The invasion halted the Cambodian genocide but isolated Vietnam internationally outside the Eastern Bloc. The Khmer Rouge retained its UN seat and joined a Coalition Government of Democratic Kampuchea in 1982. After Vietnamese withdrawal, the 1991 Paris Peace Agreements initiated a UN-supervised transition that restored multi-party rule and a constitutional monarchy in Cambodia by September 1993.
Belligerents & Mobilization Analysis
Side A
2 belligerents
Side B
3 belligerents
Pol Pot, Son Sann, Norodom Sihanouk.