President Ngô Đình Diệm of South Vietnam was assassinated, marking the culmination of a coup d'état led by Dương Văn Minh.

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 coup d'état.

South Vietnam, officially the Republic of Vietnam, was a country in Southeast Asia that existed from 1955 to 1975. It first garnered international recognition in 1949 as the associated State of Vietnam within the French Union, with its capital at Saigon. Since 1950, it was a member of the Western Bloc during the Cold War. Following the 1954 partition of Vietnam, it became known as South Vietnam and was established as a republic in 1955. South Vietnam was bordered by North Vietnam to the north, Laos to the northwest, Cambodia to the southwest, and Thailand across the Gulf of Thailand to the southwest. Its sovereignty was recognized by the United States and 87 other nations, though it failed to gain admission into the United Nations as a result of a Soviet veto in 1957. It was succeeded by the Republic of South Vietnam in 1975. In 1976, the Republic of South Vietnam and North Vietnam merged to form the Socialist Republic of Vietnam.

On 2 November 1963, Ngô Đình Diệm, the president of South Vietnam, was arrested and assassinated in a CIA-backed coup d'état led by General Dương Văn Minh. After nine years of autocratic and nepotistic family rule in the country, discontent with the Diệm regime had been simmering below the surface and culminated with mass Buddhist protests against longstanding religious discrimination after the government shooting of protesters who defied a ban on the flying of the Buddhist flag.

In November 1963, President Ngô Đình Diệm and the Personalist Labor Revolutionary Party of the Republic of Vietnam were deposed by a group of CIA-backed Army of the Republic of Vietnam officers who disagreed with Diệm's handling of the Buddhist crisis and the North Vietnamese and Viet Cong threat to South Vietnam. In South Vietnam, the coup was referred to as Cách mạng 1-11-63.