The Hundred-Horse Chestnut (; ) is the largest and oldest known sweet chestnut (Castanea sativa, family Fagaceae) in the world.

Located on Linguaglossa road in Sant'Alfio, on the eastern slope of Mount Etna in Sicily -- only 8 km from the volcano's crater -- it is generally believed to be 2,000 to 4,000 years old (4,000 according to botanist Bruno Peyronel