William J. Philbin (26 January 1907 - 23 August 1991) was an Irish Roman Catholic Prelate. From 1962 until his retirement, he held the title Lord Bishop of Down and Connor.
William Philbin was born in Kiltimagh in County Mayo, Ireland on 26 January 1907.
At the age of 17 he went to Maynooth, and was ordained on the 21 June 1931. He spent most of his ministry as a professor of dogmatic theology at St Patrick's College, Maynooth.
Philbin as a student was the editor of Leabhar Nuidheacht, published at Maynooth and was the joint editor of the Irish Theological Quarterly.
On 22 December 1953 Pope Pius XII appointed him Bishop of Clonfert, Ireland.
Upon the death of Bishop Daniel Mageean in 1962, Pope John XXIII appointed him the 29th Bishop of Down and Connor. His time was marked by the outbreak of the Troubles in the late 1960s.
He was succeeded as Bishop by Cahal Daly, his Peritus at the Second Vatican Council, in 1982.
Philbin died in 1991.