Gomang Co (also spelled as Guomang Cuo and Guomangcuo, ; ) is a mountain graben basin lake on the Tibetan Plateau in Xainza County within Nagqu in the Tibet Autonomous Region of China. Gomang Co has a Köppen climate classification of existing in a tundra climate. The lake's water level is controlled by its outlet toward Siling Lake, which is north of Gomang Co.