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

The hydrographic slope of Lake Bailly is accessible via a forest road (North-South direction) on the east side of the Saint-Cyr River South Valley; in addition, another forest road (East-West direction) serves the northern part of the Bailly Lake Biodiversity Reserve and connects R1015 to the west.

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

This lake is fed only by the Saint-Cyr River South (coming from the North).

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