Phanxicô Xaviê Nguyễn Văn Thuận or Francis-Xavier Nguyễn Văn Thuận (pronounced [ŋʷjə̌ˀn van tʰwə̂ˀn] (About this soundlisten), was a Cardinal in the Roman Catholic Church. He was a nephew of South Vietnam's first president, Ngô Đình Diệm, and of Archbishop Ngô Đình Thục.