The Huai Kha Khaeng Wildlife Sanctuary (Thai: เขตรักษาพันธุ์สัตว์ป่าห้วยขาแข้ง, pronounced [kʰèːt rák.sǎː pʰān sàt pàː hûaj kʰǎː kʰɛ̂ŋ]) is in Uthai Thani and Tak Provinces, Thailand.

The park was established in 1974, and is part of the largest intact seasonal tropical forest complex in Mainland Southeast Asia.

As of 2014[update] it still contained viable populations of large mammals, including gibbons, bears, elephants and Indochinese tigers, although like all other sites in mainland Southeast Asia, some species (e.g., rhinoceroses) have disappeared or have experienced severe declines.

[6] A large number of the animal and plant life diversity can be found nowhere else, with species such as the Sino-Himalayan, Indo-Burmese, Sundaic, and Indo-Chinese affinities, living in the wildlife sanctuary.

The Conservation Office in Bangkok and the chief of Huai Kha Khaeng are responsible for granting permission to those who wish to visit prohibited areas.