| Schaalsee | |
| Pushpin Map: | Schleswig-Holstein |
| Coords: | 53.5903°N 10.9144°W |
| Catchment: | 180km2 |
| Basin Countries: | Germany |
| Area: | 23.5km2 |
| Depth: | 17m (56feet) |
| Max-Depth: | 71.5m (234.6feet) |
| Residence Time: | 5 to 10 years |
| Elevation: | 35m (115feet) |
| Islands: | (Kampenwerder, Stintenburginsel, Rethwiese) |
| Cities: | Zarrentin, Seedorf |
Schaalsee is a 24km2 lake in Germany. It forms part of the border between Schleswig-Holstein (district Herzogtum Lauenburg) and Mecklenburg-Vorpommern (districts Ludwigslust-Parchim and Nordwestmecklenburg). The town of Zarrentin is located on its southern shores. Other municipalities on the lake are Seedorf, Sterley, Salem, Kittlitz and Kneese.
It was declared a biosphere reserve in 2000 (309 km2).