The rivière à la Loutre (English: Otter River) is a tributary of the Saguenay River, flowing in the municipality of Saint-Fulgence in the Le Fjord-du-Saguenay Regional County Municipality, in the administrative region of Saguenay-Lac-Saint-Jean, in Quebec, in Canada.

This source is located at: 0.8 km (0.50 mi) to the south of the course of the le Petit Bras and at 9.9 m (32 ft) to the north-west from the mouth of the river to the Otter.

From its source, at the confluence of two mountain streams, the course of the Rivière à la Loutre descends on 14.0 km (8.7 mi) according to the following segments: The mouth of the Rivière à la Loutre flows onto the north shore of the Saguenay River in the municipality of Saint-Fulgence.

This confluence of the Rivière à la Loutre is located at: From the mouth of the Rivière à la Loutre, the current follows the course of the Saguenay River eastwards to the height of Tadoussac where it meets the Saint Lawrence River.

[1] The toponym Rivière à la Loutre was formalized on December 5, 1968, at the Place Names Bank of the Commission de toponymie du Québec.