| Demenzsee | |
| Location: | Vorpommern-Greifswald, Mecklenburg-Vorpommern |
| Pushpin Map: | Mecklenburg-Vorpommern |
| Coords: | 53.5506°N 13.8006°W |
| Basin Countries: | Germany |
| Area: | 0.18km2 |
| Max-Depth: | 26m (85feet) |
| Elevation: | 49m (161feet) |
Demenzsee is a lake in the Vorpommern-Greifswald district in Mecklenburg-Vorpommern, Germany. At an elevation of 49 m, its surface area is 0.18 km2.