Fuyun County (), also known as Koktokay County (; ), is a county of Altay Prefecture, in the Xinjiang Uyghur Autonomous Region of China. It has an area of 32,237 km<sup>2</sup> with a population of 80,000. The seat of Fuyun County is in Ku Ertix Town. The Koktokay National Geopark is in Koktokay Town. The postal code of Fuyun County is 836100. The county is served by Fuyun Keketuohai Airport.
Fuyun County is divided into 5 towns and 5 townships.