Guyuan County () is a county under the administration of Zhangjiakou, Hebei, People's Republic of China. It was once part of the province of Chahar, and now borders Inner Mongolia. The area of the city is , and the population as of 2004 is 230,000. Bordering county-level divisions are Fengning Manchu Autonomous County to the east, Chicheng County and Chongli District to the south, Zhangbei and Kangbao counties to the west, and, in Inner Mongolia, Taibus Banner, Zhenglan Banner and Duolun County to the north. It is a primarily mountainous county in northern Hebei, and thus has a cold climate with long, bitter winters and mild summers.
