| Missisa River | |
| Pushpin Map: | Canada Ontario |
| Pushpin Map Caption: | Location of the river mouth in Ontario |
| Subdivision Type1: | Country |
| Subdivision Name1: | Canada |
| Subdivision Type2: | Province |
| Subdivision Name2: | Ontario |
| Subdivision Type3: | Region |
| Subdivision Name3: | Northwestern Ontario |
| Subdivision Type4: | District |
| Subdivision Name4: | Kenora |
| Source1: | Missisa Lake |
| Source1 Coordinates: | 52.2558°N -85.0769°W |
| Source1 Elevation: | 170m (560feet) |
| Mouth: | Attawapiskat River |
| Mouth Coordinates: | 53.0269°N -84.9006°W |
| Mouth Elevation: | 99m (325feet) |
| River System: | James Bay drainage basin |
The Missisa River is a river in northeastern Kenora District in northwestern Ontario, Canada.[1] It is in the James Bay drainage basin and is a right tributary of the Attawapiskat River.
The Missisa River begins at Missisa Lake and flows north to its mouth at the Attawapiskat River, which flows to James Bay.