| Tatsuushi River | |
| Name Other: | 立牛川 |
| Subdivision Type1: | Country |
| Subdivision Name1: | Japan |
| Subdivision Type2: | State |
| Subdivision Name2: | Hokkaidō |
| Subdivision Type3: | Region |
| Subdivision Name3: | Abashiri |
| Subdivision Type4: | District |
| Subdivision Name4: | Monbetsu |
| Subdivision Type5: | Municipality |
| Subdivision Name5: | Monbetsu |
| Length: | 33.3km (20.7miles) |
| Source1: | Kitami Fuji |
| Source1 Location: | Monbetsu, Hokkaidō, Japan |
| Source1 Coordinates: | 44.0167°N 143.1447°W |
| Source1 Elevation: | 1306m (4,285feet) |
| Mouth: | Shokotsu River |
| Mouth Location: | Monbetsu, Hokkaidō, Japan |
| Mouth Coordinates: | 44.2142°N 143.2311°W |
| River System: | Shokotsu River |
is a river in Hokkaidō, Japan.
The river rises on the slopes of Kitami Fuji in the Kitami Mountains. It flows 33 km in a northerly direction until it flows into the Shokotsu River.[1]