Storekalsøy or Stora Kalsøy is an island in Austevoll municipality in Hordaland county, Norway. The island lies northwest of the larger island of Hundvåko and just east of the Marstein Lighthouse. The northern part of the island is very rocky and mountainous. The highest point is the tall mountain Mjuken. The smaller islands of Nautøya and Spissøya lies just east of Stora Kalsøy. The smaller islands of Horgo, Møkster, and Litla Kalsøya lie to the south of Stora Kalsøy.