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.