Heissa or Hessa is an island in Ålesund Municipality in Møre og Romsdal county, Norway. It is the westernmost island in the municipality and it is one of the main islands in the island-city of Ålesund. The island is located west and south of the island of Aspøya, south of Giske and Valderøya, east of Godøya, and north of Sula.