Sanningasoq (old spelling: Sáningassoq) is a large oligotrophic twin lake[1] in central-western Greenland, in the Qeqqata municipality.

It is characteristic in that it is composed of two lakes connected via a narrow water passage through a broken isthmus.

[2] The 2x10 km[2] twin lake is separated from the Akuliarusiarsuup Kuua valley and Kangerlussuaq in the south by a low tundra ridge − part of the Kangaamiut dike swarm.

To the east lies a sibling Aajuitsup Tasia lake, separated from Sanningasoq by a low marshland isthmus of little relief.

The local depression part of which is occupied by the lake continues for several dozen kilometers in the west-north-western direction towards Sarfannguit and Sisimiut.