William Crolly (8 June 1780 – 8 April 1849) was the Roman Catholic Archbishop of Armagh from 1835 to 1849.
He went to Maynooth College where he excelled as a student, obtaining a first in Dogmatic Theology, in 1806, when he was also ordained a priest by Archbishop Troy. Crolly moved to Belfast in 1812 after some years lecturing, and in 1825 was appointed Bishop of Down and Connor, establishing St. Malachy's Seminary. In 1835 he was appointed Archbishop of Armagh.
He died of cholera in Drogheda, Co. Louth, in 1849.