The Xe Bang Fai River or Nam Xebangfai is a river of Laos .
Xe Bang Fai River originates in the Annamite Range on the border between Lao and Vietnam 17°3′1″N 106°20′54″E / 17.05028°N 106.34833°E.
It flows through Khammouane Province and Savannakhet Province.
Nam Theun 2 Dam released water from Nam Theun river into it, thereby increasing its flow and producing hydroelectricity in the process.
Xe Bang Fai River Cave, also known as Khoun Xe Cave (Tham in Laotian is Cave), is an immense river cave located in a remote corner of Khammouane Province. It is believed to be one of the largest river cave in the world with enormous passages some 120 meters tall and 200 meters wide, and subterranean channel 7 km long.17°22′24″N 105°50′14″E / 17.37333°N 105.83722°E