Midøya (sometimes called Mia) is an island in Midsund Municipality in Møre og Romsdal county, Norway. The 13.6-square-kilometre (5.3 sq mi) island sits at the entrance to the Romsdalsfjorden between the islands of Dryna and Otrøya. Until 1965, the island was divided between the municipalities of Sør-Aukra and Vatne.