The Martigny River is a tributary of the Turgeon River, flowing into the Municipality of Eeyou Istchee James Bay (municipality), in Jamésie, in the administrative region from Nord-du-Québec, in Quebec, in Canada.

The course of the river crosses the townships of Martigny, Martinière and Lanouillier.

The surface of the river is usually frozen from early November to mid-May, however, safe ice movement is generally from mid-November to the end of April.

The main hydrographic slopes near the Martigny River are: The Martigny River derives its source from "Lac aux Épices" (length: 3.9 kilometres (2.4 mi), altitude: 241 metres (791 ft)), located in the township of Martigny, in the municipality of Eeyou Istchee James Bay (municipality).

The toponym "rivière Martigny" was formalized on December 5, 1968, at the Commission de toponymie du Québec, when it was founded.