The Phum Duang River (Thai: แม่น้ำพุมดวง, RTGS: Maenam Phum Duang, Thai pronunciation: [mɛ̂ːnáːm pʰum duəŋ]) (rarely also named Khiri Rat River) is a river in Surat Thani Province, Southern Thailand, the main tributary of the Tapi River.
The rivers drains an area of 6,125 km² west of the Tapi watershed, mainly the eastern slopes of the Phuket mountain range. It joins the estuary of the Tapi 15 km west of Surat Thani in Phunphin district.