Devenish or Devinish[1] (from Irish Daimhinis, meaning 'ox island') is an island in Lower Lough Erne, County Fermanagh, Northern Ireland.

Aligned roughly north–south, it is about one and a quarter miles (2.0 km) long and two-thirds of a mile (1.1 km) wide.

The main place to catch a ferry to the island is at Trory Point, just outside Enniskillen.

Devenish Island is owned by the Kilravock Christian Trust.

[2] The island is in the civil parish of Devenish.