The Cuyuni River is a river in northern Guyana and eastern Venezuela. In places it serves as the border between the two countries. The Kamaria Hydroelectric Power site is located on the Cuyuni River in Guyana.
The river is a source of alluvial gold.
Ankoko Island is at the confluence of the Cuyuni and Wenamu River. Venezuela annexed the Guyanese half of the island in 1966.
