Byrtevatn is a lake in Tokke Municipality in Telemark county, Norway. The 4.8-square-kilometre (1.9 sq mi) lake is located about 10 kilometres (6.2 mi) northwest of the village of Dalen. The main natural influx comes from the river Byrteåi. Byrtevatn has a dam on the south end of the lake which regulates the surface elevation of the lake. Water from the nearby lake Botnedalsvatn flows through a tunnel into the Byrte Hydroelectric Power Station and the water is then released into this lake.