Telmen Lake () is a saltwater lake in Zavkhan Province, Mongolia. It is located in both the Nömrög and Telmen districts. Three islands are located in the lake, which is a gathering point for migratory birds. The lake has been designated an Important Bird Area by BirdLife International.
Average temperature ranges from -32 ðC in January to 12 ðC in July. From 6,210 to 3,960 years ago, as determined by radiocarbon dating, Lake Telmen was between 15 and 20m shallower than it is at present.