Frangula alnus, commonly known as the alder buckthorn, glossy buckthorn, or breaking buckthorn, is a tall deciduous shrub in the family Rhamnaceae. It is native to Europe, northernmost Africa, and western Asia, from Ireland and Great Britain north to the 68th parallel in Scandinavia, east to central Siberia and Xinjiang in western China, and south to northern Morocco, Turkey, and the Alborz and Caucasus Mountains; in the northwest of its range (Ireland, Scotland), it is rare and scattered. It is also introduced and naturalised in eastern North America.