Girouard Lake is a freshwater body of water crossed by the Mégiscane River, in the north-eastern part of Senneterre, in La Vallée-de-l'Or Regional County Municipality (RCM), in the administrative region of Abitibi-Témiscamingue, in the province of Quebec, in Canada.

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

The northern part of Girouard Lake is crossed on the Southwest by the Mégiscane River.

A long bay of 10.1 kilometres (6.3 mi) extends south in the township of Girouard.

The toponym "lac Girouard" was formalized on December 5, 1968, by the Commission de toponymie du Québec, when it was created.