Mutton Bird Island is an irregularly shaped unpopulated island located close to the south-western coast of Tasmania, Australia.

Situated some 2 kilometres (1.2 mi) south of where the mouth of Port Davey meets the Southern Ocean, the 44-hectare (110-acre) is the largest of the eight islands that comprise the Mutton Bird Islands Group.

The Mutton Bird Island is part of the Southwest National Park and the Tasmanian Wilderness World Heritage Site.

[1][2] The highest point of Mutton Bird Island is 40 metres (130 ft) above sea level.

The island is part of the Port Davey Islands Important Bird Area, so identified by BirdLife International because of its importance for breeding seabirds.