The Nemio River is a tributary of the south shore of the Gouin Reservoir, flowing in the town of La Tuque, in the administrative region of Mauricie, in Quebec, Canada.

The Nemio River flows successively into the townships of Tassé, Huguenin, Sulte, Chapman, Myrand and Lemay, on the southern shore of the Gouin Reservoir.

The surface of the Nemio River is usually frozen from mid-November to the end of April, however, safe ice circulation is generally from early December to late March.

The Nemio River originates at the mouth of Lac Dugré (length: 9.1 kilometres (5.7 mi) crescent-shaped, elevation: 443 metres (1,453 ft)).

From there, the current flows over 100.8 kilometres (62.6 mi) until Gouin dam, according to the following segments: The toponym "Nemio River" was formalized on December 5, 1968 at the Commission de toponymie du Québec, when it was created.