The Battle of Aughrim (Irish: Cath Eachroma) was the decisive battle of the Williamite War in Ireland. It was fought between the Jacobites and the forces of William III on 12 July 1691 (old style, equivalent to 22 July new style), near the village of Aughrim in County Galway.

The battle was one of the more bloody recorded fought on Irish soil – over 7,000 people were killed. It meant the effective end of Jacobitism in Ireland, although the city of Limerick held out until the autumn of 1691.