Seydozero is a lake in the Lovozersky tundra on the Kola Peninsula in Russia. "Siedi" when translated from Lappish means "sacred". The lake is located at the height of 189 m above sea level. Seydozero's length is 8 km, and its width — from 1,5 up to 2,5 km. A mountain river Elmorayok flows into the lake.