The Siem Reap River (Steung Siem Reap; Khmer: ស្ទឹងសៀមរាប) is a river flowing through Siem Reap Province, in north-west Cambodia.

The Siem Reap River was originally an offtake channel constructed during the Angkor period, used to divert water from the Puok River southward, probably to the East Baray.

This caused the bed of the channel to erode as much as 10 meters in some areas, and probably caused problems with diverting the water to the East Baray.

Over the past thousand years, the channel has gained small meanders and a unique ecosystem, and thus it is more accurate to call it a river.

This article related to a river in Cambodia is a stub.