South Vietnamese soldiers under the Roman Catholic President Ngo Dinh Diem open fire on Buddhists defying a ban on the flying of the Buddhist flag on Vesak, killing nine and sparking the Buddhist crisis.

The Huế Phật Đản shootings were the deaths of nine unarmed Buddhist civilians on 8 May 1963 in the city of Huế, South Vietnam, at the hands of the army and security forces of the government of Ngô Đình Diệm, a Roman Catholic. The army and police fired guns and launched grenades into a crowd of Buddhists who had been protesting against a government ban on flying the Buddhist flag on the day of Phật Đản, which commemorates the birth of Gautama Buddha.

Vesak, also known as Buddha Jayanti, Buddha Purnima, Visak Bochea and Buddha Day, is a holiday traditionally observed by Buddhists in South Asia and Southeast Asia, as well as in Tibet and Mongolia. It is among the most important Buddhist festivals. The festival commemorates the birth, enlightenment, and death (Parinirvāna) of Gautama Buddha in Theravada, Tibetan Buddhism, and Navayana.

The Buddhist crisis was a period of political and religious tension in South Vietnam between May and November 1963, characterized by a series of repressive acts by the South Vietnamese government and a campaign of civil resistance, led mainly by Buddhist monks.