Lake Nemenjiche is a freshwater body of the southern part of Eeyou Istchee Baie-James, in the administrative region of Nord-du-Québec, in the province of Quebec, Canada.

The surface of Lake Nemenjiche is usually frozen from early November to mid-May, however, safe ice circulation is generally from mid-November to mid-April.

This lake is located at 0.7 kilometres (0.43 mi) on the West side of the line between the Regional County Municipality (RCM) of Le Domaine-du-Roy and the Eeyou Istchee Baie-James; this demarcation constitutes the watershed between the James Bay side and the Lac Saint-Jean slope.

Of elongated shape in the North-South direction, this lake comprises about forty islands.

The mouth of this lake is located at the bottom of a bay on the West Bank at: The main hydrographic slopes near Lake Nemenjiche are: The toponym "lac Nemenjiche" was made official on December 5, 1968 by the Commission de toponymie du Québec, when it was created.