Lake Dusaux is a freshwater body of the territory of Eeyou Istchee Baie-James (municipality), in the administrative region of Nord-du-Québec, in the province of Quebec, in Canada.

Lake Dusaux begins at the foot of the Iroquois Falls in the Southeast that is fed by the Nottaway River, facing the Nestipuku Islands.

In the center of the lake, the current flows through the northwest in a zone of rapids bypassing the Desmolier Islands.

Dusaux Lake terminates downstream of Vandry Island (length: 2.6 kilometres (1.6 mi)) which is shaped like a half-moon.

The toponym "Lac Dusaux" was formalized on December 5, 1968, by the Commission de toponymie du Québec.