Kaysone Phomvihane (ໄກສອນ ພົມວິຫານ) (13 December 1920 – 21 November 1992) was the leader of the Lao People's Revolutionary Party from 1955, though Souphanouvong served in a figurehead role. He served as the first Prime Minister of the Lao People's Democratic Republic from 1975 to 1991 and then as President from 1991 until his death a year later, in 1992.
Phomvihane attended law school at Hanoi University in Hanoi, Vietnam, with Nouhak Phoumsavan. He dropped out of law school to fight the French colonialists who were in Vietnam. Later, he joined Lao nation, which was also fighting the French colonialists.
He became an active revolutionary while studying in the Indochinese capital of Hanoi during the 1940s. Lao People's Liberation Army (LPLA) was established by Kaysone Phomvihane on 20 January 1949. He was Minister of Defence of Resistance Government (of the Neo Lao Issara) the from 1950. In 1955 he was instrumental in setting up the LPRP at Sam Neua in northern Laos, and subsequently served as the Pathet Lao leader, with Souphanouvong as its figurehead. In the years which followed, he led communist forces against the Kingdom of Laos and U.S. forces. After their victory he served as Prime Minister from the founding of the Lao PDR in 1975 until 1991. He married Thongvinh Phomvihane.