Köl-Suu is an alpine lake in At-Bashy District of Naryn Region of southeastern Kyrgyzstan. It is located at 3514 m elevation in the Kakshaal Too mountain range, central Tian Shan. It is fed and drained by the river Kurumduk, a left tributary of the Kök-Kyia, which is a right tributary of the Kakshaal. It is 5 km long, and its area is 4.5 km.