Hamlagrøvatnet is a lake on the border of the municipalities of Voss and Kvam in Vestland county, Norway. The 10.3 km2 lake is the largest lake in all of Hordaland county. The lake is located about 17 km southeast of the village of Dalekvam and about 10 km south of the village of Evanger. The lake sits at the eastern end of the Bergsdalen valley and it is regulated at elevation of 588 to 560 m above sea level. The lake is a reservoir on the river Bergsdalselvi which has four hydroelectric power stations on it. The lake is surrounded by many holiday cottages.