Scholars have portrayed the 1963 ‘Buddhist crisis’ in South Vietnam as a struggle for religious freedom, as a political conspiracy, or as a manifestation of ancient religious beliefs and practices. This paper, in contrast, argues that the crisis emerged from a clash of modernizing visions. The Buddhist-led protests that took place in South Vietnam in 1963 were linked to the Vietnamese Buddhist revival, a nationalist reform movement that began during the early twentieth century. The protests also reflected growing Buddhist anxieties about the Ngo Dinh Diem government's nation-building agenda for South Vietnam. By the time the crisis began, Buddhist leaders had concluded that this agenda (which Diem referred to as the ‘Personalist Revolution’) was incompatible with their plans to realize Vietnam's destiny as a ‘Buddhist nation’. In addition to reinterpreting the origins of the crisis, this paper examines how the course of events was shaped by the personalities and agendas of particular Buddhist and government leaders, and especially by fierce rivalries among members of Diem's family. These internal tensions help to explain the failure of attempts to end the crisis through negotiations, as well as Diem's decision to crush the movement by force in August 1963.