Duno is a comune (municipality) in the Province of Varese in the Italian region Lombardy, located about 60 km northwest of Milan and about 14 km northwest of Varese. As of 31 December 2004, it had a population of 163 and an area of 2.5 km².[1]

Duno borders the following municipalities: Brissago-Valtravaglia, Casalzuigno, Cassano Valcuvia, Cuveglio, Mesenzana, Porto Valtravaglia.