| Tokachi River | |
| Name Other: | Tokachi-gawa, Tokapci |
| Pushpin Map: | Japan |
| Subdivision Type1: | Country |
| Subdivision Name1: | Japan |
| Subdivision Type2: | State |
| Subdivision Name2: | Hokkaidō |
| Subdivision Type3: | Region |
| Subdivision Name3: | Tokachi |
| Subdivision Type4: | District |
| Subdivision Name4: | Kamikawa, Nakagawa |
| Subdivision Type5: | Municipalities |
| Subdivision Name5: | Shintoku, Toyokoro |
| Length: | 156km (97miles) |
| Discharge1 Avg: | 71m3/s |
| Source1 Location: | Shintoku, Hokkaidō, Japan |
| Mouth: | Pacific Ocean |
| Mouth Location: | Toyokoro, Hokkaidō, Japan |
| Mouth Coordinates: | 42.695°N 143.6661°W |
| Mouth Elevation: | 0m (00feet) |
| Basin Size: | 9010km2 |
| Basin Population: | 340,000 |
is a river in Hokkaidō, Japan.
In 1820, the explorer Takeshiro Matsuura (松浦 武四郎) proposed "Tokachi" as the name of the surrounding Tokachi Province, with each character corresponding to a Japanese homophone. The province was named after this river, which in turn was derived from the Ainu language word .
Although the exact origins of "tokapci" were unknown, Hidezo Yamada, an Ainu language researcher, proposed these origins: