The Grebe River is a river in Fiordland, New Zealand. It arises north-west of Lake Monowai in an area once part of the lake but cut off by an enormous landslide about 13,000 years ago. The river now flows north, between the Townley Mountains to the west, and the Hunter Mountains to the east, and into Lake Manapouri's South Arm. Its major tributaries are Jaquiery Stream, Florence Stream, Emerald Stream, and Percy Stream, all from the west.