Masteyra Island (Bulgarian: остров Мастейра, romanized: ostrov Masteyra, IPA: [ˈɔstrof mɐˈstɛjrɐ]) is a rocky island 700 m long in east-west direction and 200 m wide lying in Perrier Bay on the northwest coast of Anvers Island in the Palmer Archipelago, Antarctica.

It is separated from Anvers Island to the east-southeast by a 1.13 km wide passage.

The island is named after the ancient Thracian settlement and fortress of Masteyra in Southern Bulgaria.

This article includes information from the Antarctic Place-names Commission of Bulgaria which is used with permission.

This Anvers Island location article is a stub.