Joseph Duffy (born 3 February 1934) is the Roman Catholic Bishop of Clogher in Ireland, a position he has held since 1979. He resides in Monaghan Town, County Monaghan, Ireland.

Joseph Duffy was the eldest of three boys and one girl born to Edward Duffy and Brigid MacEntee of Annagose, Newbliss, County Monaghan. He was educated at St. Louis' Infant School, Clones, County Monaghan and at St. Macartan’s College, Monaghan, where he was a boarder for five years.

He studied for the priesthood at St Patrick's College, Maynooth, and was ordained priest for the Diocese of Clogher on 22 June 1958. After his ordination to the priesthood he continued his studies in Irish and completed a thesis on the dialect of South Tipperary for a Master’s degree in the National University of Ireland in 1960.