Fermoy (; formerly also Armoy) is a barony in County Cork in Ireland. It is bordered by the baronies of Orrery and Kilmore to the north-west; Duhallow to the west; Barretts to the south-west; Barrymore to the south; Condons and Clangibbon to the east; and Coshlea, County Limerick to the north. It is bounded to the south by the Nagle Mountains and the valley of the Munster Blackwater. The Ballyhoura Mountains mark the northern boundary. A tributary of the Blackwater, the Awbeg has two branches in its upper stretches; one branch forms the northern boundary while the other near Buttevant, forms the western limit. To the east, lies another Blackwater tributary, the Funcheon. Anomalously, the namesake town of Fermoy is actually in the barony of Condons and Clangibbon. The town with the greatest population in the barony is Mallow (8578 people per Census of 2006).