The Rivière du Loup (French pronunciation: [ʁivjɛʁ dy lu]) is a river in eastern Quebec, Canada, which empties on the south shore of Saint Lawrence River at the city of Rivière-du-Loup, which is part of the regional county municipality (RCM) Rivière-du-Loup, in the administrative region of Bas-Saint-Laurent.

The Rivière du Loup (English: "river of the Wolf") has its source in Saint-Pierre Lake (Lac Saint-Pierre) in the geographic township of Painchaud in the Kamouraska Regional County Municipality, which is in the Notre Dame Mountains and the Zone d'exploitation contrôlée (English: Controlled Harvesting Zone) of Zec Chapais.

The Rivière du Loup flows to the north over 101.3 kilometers (63 miles), coursing through the regional county municipalities of: At its mouth, the Rivière du Loup pours over a long ledge (at low tide) in the "Cayes to Carrier Bay" which is bordered on the north side by the Pointe-de-Rivière-du-Loup.

From Malin Rock, this edge advances towards the southwest in the St. Lawrence River over a length of 1.6 km (1 mile), including the end where a marina is fitted.

The river's mouth is located in front of the Île aux Lièvres (English: Island of Hare) and the Île Blanche (English: White Island), located 10 km (6 miles) offshore and part of the municipality of Saint-André-de-Kamouraska.