Lake Leksozero (Russian: Лексозеро, Finnish: Lieksajärvi) is a large freshwater lake in the Republic of Karelia, Russia. It has an area of 166 km² and an average depth of 8.6 m. It freezes up in November and stays icebound until May. There are many islands on the lake. Leksozero is used for fishery. The lake drains through the river Lieksanjoki that flows into the lake Pielinen in Northern Karelia, Finland.