Yunaska (Aleut: Yunax̂sxa;[1] Russian: Юнаска) is an uninhabited island which is the largest of the Islands of Four Mountains group[2] in the Aleutian Islands of southwestern Alaska, United States.

The island comprises two volcanic mountains, with a valley between.

The western mountain is composed of four overlapping and eroded stratovolcanoes, with a cinder cone field at the western end.

The eastern mountain is a large shield volcano with two overlapping summit calderas, which last erupted in 1937.

This article about a location in the Aleutians West Census Area, Alaska is a stub.