The Phetchaburi River (, , ]) is a river in western Thailand. It has its source in the Tenasserim Hills, in the Kaeng Krachan National Park, Kaeng Krachan district and flows through Tha Yang, Ban Lat, Mueang Phetchaburi and mouths into the Bay of Bangkok in Ban Laem district. It is long, most of which is within the Phetchaburi Province. It is the backbone of this province.