Senftenberger See, Artificial lake in Senftenberg, Germany

Senftenberger See is a reservoir in Senftenberg, Germany, with 1,300 hectares of water surface and an 18-kilometer shoreline. The sandy beaches extend for 7 kilometers along the waterfront and offer swimming areas for visitors at several points around the lake.

The site was formerly an open-pit lignite mine, flooded between 1967 and 1972 with water from the Black Elster river. The conversion created one of the largest artificial lakes in Brandenburg and transformed the landscape from a mining zone into a recreation area.

The lake's Sorbian name, Złykomorojski jazor, comes from the village of Zły Komorow (Senftenberg), and the German name refers to the town beside it. The first beach section opened in 1973, and the lake has since drawn bathers, surfers and sailors. Three official naturist beaches lie on the north shore, at the campsite west of Großkoschen and at the Südsee.

The marina built in 2013 offers space for boats and has a floating dock for mooring watercraft. Visitors find several water access points around the shore, with beaches on the north side and near Großkoschen particularly easy to reach.

The lake's 250-hectare wooded island is itself built from dumped spoil from the former Niemtsch opencast mine. It was declared a nature reserve in 1981 and may not be entered because of the high risk of slope collapse. The lake is also a state waterway, open to motorboats at up to 12 km/h.