The rivière des Petites Îles (Petites Îles River) is a tributary of the south shore of the Saguenay River flowing successively in the municipalities of Petit-Saguenay and Baie-Sainte-Catherine, in Regional County Municipality (MRC) of Le Fjord-du-Saguenay, in Quebec, Canada.

The upper part of this valley is served indirectly by Route 170 which connects Saint-Siméon to the village of Petit-Saguenay which passes over the north shore of the Noire River.

Despite its mountainous terrain, the valley of the "Petites Îles River" has some secondary forest roads for forestry and recreational tourism purposes.

The surface of Petites Îles River is usually frozen from the beginning of December to the end of March, however, safe ice circulation is generally from mid-December to mid-March.

[5] The toponym "Rivière des Petites Îles" was formalized on December 5, 1968, at the Bank of Place Names of the Commission de toponymie du Québec.