The Rivière Bec-Scie is a tributary of the Gulf of Saint Lawrence, flowing in the municipality of L'Île-d'Anticosti, in the Minganie Regional County Municipality, in the administrative region of Côte-Nord, in province of Quebec, in Canada.

The main forest road (east-west) of Anticosti Island serves the upper part of this valley.

[1] The Bec-Scie river has its source at Lake Valiquette (length: 1.6 km (0.99 mi); altitude: 83 m (272 ft)) located in the western part of Anticosti Island.

At its mouth, the current of the river forms a channel up to about 1.5 km (0.93 mi) at low tide in the sandstone.

[1] The toponymic designation "Bec-Scie" refers to Mergus, a genus of fish-eating ducks whose French common name is harle.