Matheson Lake is a lake in Meadow Lake Provincial Park in the Canadian Province of Saskatchewan in the boreal forest ecozone of Canada. The lake is located near the centre of the park, north of the Waterhen River, west of Vivian Lake and south of Peitahigan Lake. Several small streams feed into the lake and the outflow is at the southern shore, which feeds into the Waterhen River, a tributary of Beaver River. The Beaver River, in turn, flows north into Lac Île-à-la-Crosse and the Churchill River, a major tributary in the Hudson Bay drainage basin.