The Eastern Breithorn but also referred as the western Breithorn Twin, is a peak of the Pennine Alps, located on the border between Switzerland and Italy, between the canton of Valais and the region of Aosta Valley. It is part of the Breithorn range, located east of the Theodul Pass. It lies between the Central Breithorn and its other twin, the Gendarm. On its north side it overlooks the Breithorn Glacier.