Grimnitzsee (German pronunciation) is a lake in Landkreis Barnim, Brandenburg, Germany. At an elevation of 64 m, its surface area is 7.8 km. It is situated in the municipality of Joachimsthal.

• Werbellinsee

• Media related to Grimnitzsee at Wikimedia Commons
• Nixdorf, B.; et al. (2004), "Grimnitzsee", Dokumentation von Zustand und Entwicklung der wichtigsten Seen Deutschlands (in German), Berlin: Umweltbundesamt, p. 15