The Khmer Rouge (, French: [kmɛʁ ʁuʒ], Red Khmers; Khmer: ខ្មែរក្រហម Khmae Kro-hom) was the name popularly given to the followers of the Communist Party of Kampuchea (CPK) and by extension to the regime through which the CPK ruled in Cambodia between 1975 and 1979. The name had originally been used in the 1950s by Norodom Sihanouk as a blanket term for the Cambodian left.
The Khmer Rouge army was slowly built up in the jungles of Eastern Cambodia during the late 1960s, supported by the North Vietnamese army, the Viet Cong and the Pathet Lao. The Khmer Rouge won the Cambodian Civil War when in 1975 they captured the Cambodian capital and overthrew the government of the Khmer Republic. Following their victory, the Khmer Rouge led by Pol Pot, Nuon Chea, Ieng Sary, Son Sen and Khieu Samphan renamed the country as Democratic Kampuchea and immediately set about forcibly evacuating the country's major cities. The regime would go on to murder hundreds of thousands of their perceived political opponents. Ultimately, the Cambodian genocide would lead to the deaths of 1.5 to 3 million people, around 25% of Cambodia's population.
The Khmer Rouge regime was highly autocratic, xenophobic, paranoid and repressive. The genocide was in part the result of the regime's social engineering policies. Its attempts at agricultural reform through collectivisation led to widespread famine while its insistence on absolute self-sufficiency, even in the supply of medicine, led to the death of many thousands from treatable diseases such as malaria. The Khmer Rouge's racist emphasis on national purity included several genocides of Cambodian minorities. Arbitrary executions and torture were carried out by its cadres against perceived subversive elements, or during genocidal purges of its own ranks between 1975 and 1978.
The regime was removed from power in 1979 when Vietnam invaded Cambodia and quickly destroyed most of the Khmer Rouge's army. The Khmer Rouge then fled to Thailand whose government saw them as a buffer force against the Communist Vietnamese. The Khmer Rouge continued to fight the Vietnamese and the new People's Republic of Kampuchea government during the Cambodian–Vietnamese War which ended in 1989.
The Cambodian governments-in-exile (including the Khmer Rouge) held onto Cambodia's United Nations seat (with considerable international support) until 1993, when the monarchy was restored and the country's name was changed to the Kingdom of Cambodia. A year later, thousands of Khmer Rouge guerrillas surrendered themselves in a government amnesty.
In 1996, a new political party called the Democratic National Union Movement was formed by Ieng Sary, who was granted amnesty for his role as the deputy leader of the Khmer Rouge. The organization was largely dissolved by the mid-1990s and finally surrendered completely in 1999. In 2014, two Khmer Rouge leaders, Nuon Chea and Khieu Samphan, were jailed for life by a United Nations-backed court, which found them guilty of crimes against humanity for their roles in the Khmer Rouge's genocidal campaign. The Khmer Rouge dissolved sometime in December 1999.