Selja is a small island in the municipality of Selje in Sogn og Fjordane county, Norway. It has been formerly known as Sellø or Selø. The island is located in the Sildagapet bay, just west of Selje harbor.
The island is mainly known for its connection to Saint Sunniva, who, according to legend, landed and died there in the late 10th century. Today, the ruins of a monastery named "Sankta Sunniva kloster" (Selje Abbey) is the only notable feature on the island. The cave of Saint Sunniva and the ruins of an early (and very small) cathedral are also located on the island. The cathedral is the predecessor of the Ancient Diocese of Bergen.
The painter Bernt Tunold grew up on the island, where his parents had established a farm on the church grounds.