Son Sann (Khmer: សឺន សាន, Sœn San [sɨːn saːn]; 5 October 1911 – 19 December 2000) was a Cambodian politician and anti-communist resistance leader who served as the 22nd Prime Minister of Cambodia (1967–68) and later as President of the National Assembly (1993).
He re-entered politics as a member of the Sangkum party and served in several governments in the late 1950s to the early 1960s holding various posts before becoming president of the National Bank of Cambodia (1955–1968).
He continued with these efforts even after the October proclamation of the Khmer Republic and by late 1971 he had gained the support of politicians and diplomats in Cambodia, France and China.
In 1978, he formed the Khmer People's National Liberation Front (KPNLF) to unite anti-communist refugees on the Thai-Cambodia border following the 1978 Vietnamese invasion of Cambodia.
In the late 1980s and early 1990s, Son Sann drew some limited military and financial support from the United States, which sought to assist his movement as part of the Reagan Doctrine effort to counter Soviet and Vietnamese involvement in Cambodia.
One of the Reagan Doctrine's principal architects, The Heritage Foundation's Michael Johns, visited with Sonn Sann and KPNLF forces in Cambodia in 1987, and returned to Washington urging expanded U.S. support for the KPNLF and the resistance forces of Norodom Sihanouk as a third alternative to both the Vietnamese-installed and supported Cambodian government and the Khmer Rouge, which also was resisting the government.