Nilsebuvatnet is a lake in the municipalities of Forsand and Hjelmeland in Rogaland county, Norway. The 2.47-square-kilometre (0.95 sq mi) lake lies in the Lyseheiane mountains about 13 kilometres (8.1 mi) north of the village of Lysebotn and about 25 kilometres (16 mi) east of the village of Årdal. The lake is regulated by a small dam on the southwest corner of the lake. The dam provides water for the Lysebotn power station. The lake drains out into the river Storåna which flows westward towards Årdal. The lake is accessible by a small service road from Lysebotn which leads up to the dam.