Uilliam Ó Fearghail (William O’Ferral; died 1516) was a Roman Catholic prelate:^[2] he served as Bishop of Ardagh (1480–1516).^[1]

Uilliam Ó Fearghail was ordained a priest in the Order of Cistercians.^[1] On 4 Aug 1480, Uilliam Ó Fearghail was appointed by Pope Sixtus IV as Bishop of Ardagh.^[1] He was consecrated bishop on 11 August 1482.^[1] He served as Bishop of Ardagh until his death in 1516.^[1] While bishop, he served as principal co-consecrator of Michael Hildebrand, Archbishop of Riga (1484).^[1]