Storvatnet (also known as Ytre Storvatnet) is a lake in the counties of Aust-Agder, Vest-Agder, and Rogaland, Norway. The majority of the area is located in the municipality of Bykle. It is part of the Svartevatnet reservoir that empties into the Sira River system. The lake is located just south of the lake Blåsjø and southwest of Botsvatn.