| Big Willow 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 Coordinates: | 52.3281°N -82.4103°W |
| Source1 Elevation: | 42m (138feet) |
| Mouth: | James Bay |
| Mouth Coordinates: | 52.6781°N -81.8914°W |
| Mouth Elevation: | 0m (00feet) |
| River System: | James Bay drainage basin |
The Big Willow River is a river in northeastern Kenora District in northwestern Ontario, Canada.[1] It is a tributary of James Bay.
The Big Willow River begins in muskeg and flows north-northeast to its mouth at James Bay.