Mount Plymouth or Mount Osorno is a conspicuous peak rising to 520 m (1,710 ft) in the northeast extremity of Dryanovo Heights, Greenwich Island in the South Shetland Islands, Antarctica. The peak has precipitous and partly ice-free northern slopes, and surmounts Teteven Glacier to the northwest, Quito Glacier to the northeast and Traub Glacier to the southeast.
The feature was charted by the Discovery Investigations and named after the city of Plymouth, England.