(died 2 September 1748) was an Irish Roman Catholic clergyman who served as Bishop of Ossory from 1736 until his death in 1748.
Almost ten years later, he was appointed Bishop of Ossory by a papal brief on 5 October 1736.
[1][3] When his uncle, William O'Shaughnessy, died in 1744, he became the Chief of the Name and commenced a lawsuit in the Court of Common Pleas to recover the ancient O'Shaughnessy estates at Gort in County Galway, Ireland.
The property had been taken from Roger O'Shaughnessy by King William III in 1690, and given to Thomas Prendergast in 1697.
Despite a protracted court case, which lasted beyond the life of the bishop, it was finally ruled in favour of the Prendergasts, the penal laws against Catholics tending to defeat the rights of the O'Shaughnessies.