The Petite rivière à l'Ours - South (English: Little river of the Bear) is a tributary of rivière à l'Ours, flowing successively in the unorganized territory of Lac-Ashuapmushuan and in the municipality of Sainte-Hedwidge, in the Le Domaine-du-Roy Regional County Municipality, in the administrative region of Saguenay–Lac-Saint-Jean, in the province of Quebec, in Canada.

The surface of the Little Bear River is usually frozen from the beginning of December to the end of March, except the rapids areas; however, safe traffic on the ice is generally from mid-December to mid-March.

The Little Bear River takes its source from the Three Islands Lake (length: 1.8 km (1.1 mi); altitude: 450 m (1,480 ft)), in Zec de la Lièvre in the unorganized territory of Lac-Ashuapmushuan.

The mouth of this small lake is located at: From the mouth of the Three Islands lake, the Little Bear River flows over 11.2 km (7.0 mi) with a drop of 100 m (330 ft) especially in forest areas, according to following segments: The Little Bear River flows into a bend on the southeast bank of the rivière à l'Ours.

The toponym "Little Bear River" was formalized on February 25, 1976, at the Place Names Bank of the Commission de toponymie du Québec.