| Râul Negru | |
| Map: | Raul Negru.png |
| Subdivision Type1: | Country |
| Subdivision Name1: | Romania |
| Subdivision Type2: | Counties |
| Subdivision Name2: | Covasna, Brașov |
| Length: | 88km (55miles) |
| Source1: | Nemira Mountains |
| Mouth: | Olt |
| Mouth Location: | Lunca Câlnicului |
| Mouth Coordinates: | 45.7603°N 25.7567°W |
| Basin Size: | 2349km2 |
| Tributaries Left: | Ghelința, Covasna, Tărlung |
| Tributaries Right: | Cașin |
The Râul Negru (hu|Feketeügy; literally meaning "Black River") is a left tributary of the river Olt in Romania. It joins the Olt in Lunca Câlnicului.[1] The Râul Negru flows through the villages Lemnia, Lunga, Catalina, Hătuica, Surcea, Telechia, Bita, Reci, Sântionlunca, Ozun, Băcel, Chichiș and Lunca Câlnicului. Its length is 88km (55miles) and its basin size is 2349km2.
The following rivers are tributaries to the Râul Negru (from source to mouth):