| Guaju River | |
| Pushpin Map: | Brazil |
| Pushpin Map Caption: | Location of mouth |
| Source1 Location: | Paraíba state |
| Mouth Location: | Rio Grande do Norte state |
| Mouth Coordinates: | -6.4878°N -34.9683°W |
| Subdivision Type1: | Country |
| Subdivision Name1: | Brazil |
| Subdivision Type2: | State |
| Subdivision Name2: | Paraíba, Rio Grande do Norte |
The Guaju River is a river in Northeastern Brazil. It forms part of the border between the Paraíba and Rio Grande do Norte states.[1]