| Manacapuru River | |
| Source1 Location: | Amazonas state |
| Mouth Location: | Amazon River (Solimões section) |
| Subdivision Type1: | Country |
| Subdivision Name1: | Brazil |
| Discharge1 Avg: | 550m3/s |
Manacapuru River is a river of Amazonas state in north-western Brazil. It flows into the Amazon River (Solimões section) at the city of Manacapuru, about 80km (50miles) upstream (west) from Manaus. Parts of the river are very broad, appearing as elongated lakes, with the uppermost known as Lago Grande de Manacapuru ("Large Manacapuru Lake") and the lowermost, near where it merges into the Amazon, as Lago Manacapuru ("Lake Manacapuru").