| Simuay River | |
| Pushpin Map: | Mindanao mainland#Philippines |
| Subdivision Type1: | Country |
| Subdivision Name1: | Philippines |
| Subdivision Type2: | Region |
| Subdivision Name2: | Maguindanao, Bangsamoro Autonomous Region |
| Length: | 81km (50miles) |
| Source1: | Piapayungan Range |
| Source1 Location: | Mount Ragang |
| Source1 Elevation: | 9236feet |
| Basin Size: | 627km2 |
The Simuay River is a river in the Philippines with its source at Lanao del Sur in the Piapayungan range, and its mouth at is at Illana Bay through the Mindanao River.