Krumme Lanke, Public lake in Steglitz-Zehlendorf, Germany.

Krumme Lanke is a 1,100-metre-long, tube-shaped lake on the southwestern edge of Berlin's Grunewald forest, with a circumference of about 2.5 km, a maximum depth of 6.6 m and a surface area of roughly 154,000 m². Its dark blue water meets a continuous tree line of pines and broadleaf trees, with no beach or path visible along the far shore.

In 1251 the Cistercian monks of Lehnin Abbey bought the village of Crumense by the lake for 150 marks from the Ascanian margraves Johann I and Otto III; the village, named after the crooked lake, was abandoned soon after and is absent from Charles IV's land register of 1375. Between 1938 and 1940 the GAGFAH built the SS-Kameradschaftssiedlung Krumme Lanke here, a forest settlement placed under monument protection in 1992.

The lake's name comes from the abandoned village of Crumense, bought by Lehnin Abbey in 1251; in Middle Low German it means a place by a crooked lake, and "Lanke" derives from a regional Polabian word for a body of water. Berlin performers have celebrated it in song, from Fredy Sieg's 1923 Das Lied von der Krummen Lanke to Insterburg & Co. in 1973 and Gebrüder Blattschuss in 1980.

The U3 station Krumme Lanke lies about a kilometre from the shore, not at the lake itself. A 2.5 km path circles the water and is used by walkers and joggers. The northern bank has a flat sandy bathing spot and belongs to the Grunewald dog-off-leash area; on the southern bank dogs must be kept on a lead and kept away from lawns and bathing spots.

On 4 December 1970, salvage work began in the western part of the lake on a British bomber that crashed there in 1944 during an Allied air raid. Bombs, fuel tanks and oil were suspected on board, and the wreckage was thought to lie scattered within 50 m, partly under a five-metre layer of mud.