| Langes Wasser | |
| Mouth Coordinates: | 51.2024°N 14.2982°W |
| Progression: | Hoyerswerdaer Schwarzwasser→ |
| Subdivision Type1: | Country |
| Subdivision Name1: | Germany |
| Subdivision Type2: | States |
| Subdivision Name2: | Saxony |
Langes Wasser is a river of Saxony, Germany. It is a right tributary of the Hoyerswerdaer Schwarzwasser, which it joins in Pietzschwitz.