| Gropenborn | |
| Mouth Coordinates: | 51.7004°N 10.4332°W |
| Subdivision Type1: | Country |
| Subdivision Type2: | State |
Gropenborn is a river of Lower Saxony, Germany.
It rises to over 560 meters above sea level and flows mostly to the northwest, where it is separated by the Gropenbornskopf from the Sieber. After about it discharges an altitude of less than 340 m northeast of the village Sieber in the district of Göttingen into the Sieber.
The dominant organism group are caddisflies with 12 species.