| Rat Portage 38B | |
| Official Name: | Rat Portage Reserve No. 38B |
| Settlement Type: | Indian reserve |
| Pushpin Map: | Canada Ontario |
| Pushpin Mapsize: | 200 |
| Coordinates: | 49.7333°N -120°W |
| Subdivision Type: | Country |
| Subdivision Type1: | Province |
| Subdivision Type2: | District |
| Subdivision Name2: | Kenora |
| Subdivision Type3: | First Nation |
| Subdivision Name3: | Anishinabe of Wauzhushk Onigum |
| Area Land Km2: | 18.88 |
| Population Footnotes: | [1] |
| Population Total: | 394 |
| Population As Of: | 2011 |
| Population Density Km2: | 20.9 |
Rat Portage 38B is a First Nations reserve on Lake of the Woods in Kenora District, Ontario. It is one of the reserves of the Anishinabe of Wauzhushk Onigum.