Haikou is the capital of Hainan Province, China.
Haikou may also refer to:
- Haikou, Fuqing, town in Fuqing County, Fuzhou City, Fujian, China
- Haikou Subdistrict (formerly, Haikou Town), in Xishan District, Kunming, Yunnan, China
- Several other towns named Haikou; see zh:海口镇