Pseudocalotes khaonanensis is the largest agamid lizard in the genus Pseudocalotes. Endemic to Thailand, it is found only in the Khao Nan mountain range in (Khao Nan National Park), located in the Nakhon Si Thammarat Province of Southern Thailand. Found at high elevation in Cloud/Montane Forests in the stunted tree growth associated with this habitat, in trees rich with epiphyte growth.