Stakkastadvatnet is a lake on the border of Rogaland and Hordaland counties in Norway. The 2.92-square-kilometre (1.13 sq mi) lake mostly lies in Rogaland along the municipal borders of Haugesund and Tysvær. A very small portion of the northern part of the lake crosses over into the municipality of Sveio in Hordaland county. The lake lies about 6 kilometres (3.7 mi) northeast of the town of Haugesund. The lake has a small dam on the northwestern edge of the lake. The natural outlet of the lake flows through the dam and into the nearby lake Vigdarvatnet, located to the north.