| Lake of the Woods 31H | |
| Official Name: | Lake of the Woods Indian Reserve No. 31H |
| Settlement Type: | Indian reserve |
| Pushpin Map: | Canada Ontario |
| Pushpin Mapsize: | 200 |
| Coordinates: | 49.1167°N -137°W |
| Subdivision Type: | Country |
| Subdivision Type1: | Province |
| Subdivision Type2: | District |
| Subdivision Name2: | Rainy River |
| Subdivision Type3: | First Nation |
| Subdivision Name3: | Naongashiing |
| Area Land Km2: | 9.64 |
| Population As Of: | 2011 |
Lake of the Woods 31H is a First Nations reserve on Big Island in Lake of the Woods, northwestern Ontario. It is one of the reserves of the Anishnaabeg of Naongashiing.