Fleesensee is a lake in the Mecklenburgische Seenplatte district in Mecklenburg-Vorpommern, Germany. At an elevation of 62 metres (203ft), its surface area is 10.78 square kilometres (4.16sqmi).
The lake is both fed and drained by the Elde river. On its shore, located in a part of the municipality Göhren-Lebbin, there is a large vacation resort that was opened in 2000.