| Marten River | |
| Pushpin Map: | Canada Ontario |
| Pushpin Map Caption: | Location of the mouth of the Marten River in Ontario |
| Subdivision Type1: | Country |
| Subdivision Name1: | Canada |
| Subdivision Type2: | Province |
| Subdivision Name2: | Ontario |
| Subdivision Type3: | Region |
| Subdivision Name3: | Northeastern Ontario |
| Subdivision Type4: | District |
| Subdivision Name4: | Nipissing |
| Subdivision Type5: | Municipality |
| Subdivision Name5: | Temagami |
| Length: | 46km (29miles) |
| Source1: | Lower Redwater Lake |
| Source1 Location: | Milne Township |
| Source1 Coordinates: | 46.8842°N -79.6339°W |
| Source1 Elevation: | 300m (1,000feet) |
| Mouth: | Red Cedar Lake |
| Mouth Location: | McCallum Township |
| Mouth Coordinates: | 46.7303°N -79.8911°W |
| Mouth Elevation: | 280m (920feet) |
The Marten River is a river in Nipissing District, Ontario, Canada. Situated in the Municipality of Temagami, it begins at the southern end of Lower Redwater Lake at an elevation of . It flows westwards to the hamlet of Marten River then to Red Cedar Lake where it is in elevation. The Marten River has a total length of .[1]