| Cuieiras River | |
| Pushpin Map: | Brazil |
| River System: | Demini River |
| Source1 Location: | Amazonas state |
| Mouth Location: | Demini River |
| Mouth Coordinates: | 0.4551°N -62.7251°W |
| Subdivision Type1: | Country |
| Subdivision Name1: | Brazil |
Cuieiras River (Portuguese: Rio Cuieiras) is a river of the Barcelos municipality of Amazonas state in north-western Brazil.It is a tributary of the Demini River.
The river rises near the Serra do Aracá, the mountain after which the Serra do Aracá State Park is named, and provides a route to the foot of the mountain.