The Lessard River is a tributary of the rivière Franquelin Branche Ouest, flowing in the unorganized territory of Rivière-aux-Outardes, in the Manicouagan Regional County Municipality, in the administrative region of Côte-Nord, in the province of Quebec, in Canada.

The Lessard River draws its source from a small lake (length: 0.4 km (0.25 mi); altitude: 176 m (577 ft)) located in the unorganized territory of Rivière-aux-Outardes.

This mouth is located at: From its source, the Lessard River flows over 5.8 km (3.6 mi) with a drop of 76 m (249 ft), especially in forest areas, according to the following segments: The Lessard river flows on the southwest bank of the rivière Franquelin Branche Ouest.

This confluence is located southeast of Lac à l'Oignon, either: From the mouth of the Lessard river, the current descends on 4.3 km (2.7 mi) the course of the rivière Franquelin Branche Ouest, then on 19.0 km (11.8 mi) the course of the Franquelin river to the north shore of the estuary of Saint Lawrence.

The toponym "Lessard River" was formalized on December 5, 1968, at the Place Names Bank of the Commission de toponymie du Québec.