Prachuap Khiri Khan is one of the western provinces (changwat) of Thailand. It is in the northern part of the Malay Peninsula, some 240 km (149 mi) south of Bangkok. Neighboring provinces include Phetchaburi to the north and Chumphon to the south. To the west, it borders Tanintharyi Region of Myanmar.

The provinces of Thailand are administrative divisions of the government of Thailand. The country is divided into 76 provinces proper, with one additional special administrative area. They are the primary local government units and act as juristic persons. They are divided into amphoe (districts) which are further divided into tambon, the next lower level of local government.