Sentinel Island is a granite island, with an area of 10 ha, in south-eastern Australia. It is part of Tasmania’s Sentinel Island Group, lying in eastern Bass Strait off the north-west coast of Flinders Island in the Furneaux Group. Until 1985 it was used for grazing sheep.

The Sentinel Island Group includes:

Seabirds and waders recorded as breeding on the island include little penguin, short-tailed shearwater, common diving-petrel, white-faced storm-petrel, silver gull, Pacific gull, Caspian tern and sooty oystercatcher. The metallic skink is present.

• List of islands of Tasmania

39°50′S 147°46′E / 39.833°S 147.767°E / -39.833; 147.767