Lake Leśnia (Polish Jezioro Leśniańskie, German Marklissa-Talsperre) is a small artificial lake, located on the Kwisa river, between towns of Leśna and Gryfow Slaski in Lower Silesian Voivodeship, southwestern Poland.

Most workers employed during construction came from Austria and Italy, and total cost was estimated at 1,270,00 reichsmarks.

Total area of the lake is 140 hectares, and volume - 15 million cubic metres.

Between 1905 and 1907, a hydroelectric power plant was built there, for 800,000 marks, funded by the government of Silesia.

The lake is a popular summer vacation centre, with several campsites and watersports facilities.