Ngô Đình Diệm was a South Vietnamese politician who was the final prime minister of the State of Vietnam (1954–1955) and later the first president of South Vietnam from 1955 until his capture and assassination during the CIA-backed 1963 South Vietnamese coup.

The State of Vietnam was a governmental entity in Southeast Asia that existed from 1949 until 1955, first as a member of the French Union and later as a country. The state claimed authority over all of Vietnam during the First Indochina War, although large parts of its territory were controlled by the Democratic Republic of Vietnam.