The Sagan River is a seasonal river in southern Ethiopia.
Rising in the Ethiopian Highlands mountains east of Lake Chamo, it flows south then west to join the Weito River at 5°13′N 37°1′E / 5.217°N 37.017°E.
It defines part of the boundary between the Southern Nations, Nationalities, and Peoples' Region and the Oromia Region.
Tributaries of the Sagan include the Talpeena.