Namsvatnet (Southern Sami: Nååmesjenjaevrie) is a lake in the municipality of Røyrvik in Nord-Trøndelag county, Norway. The river Namsen formerly was the primary outlet, but the lake has been regulated for hydroelectric generation since 1959 and part of the water is diverted south towards a power station. The lake is fed by three main sources within Børgefjell National Park: the river Storelva which comes from the lake Jengelvatnet, the river Virmaelva, and the river Orelva which comes from the lake Ovrejaevrie. Namsvatnet has Arctic char, trout, and small carp.