Duno is a comune (municipality) in the Province of Varese in the Italian region Lombardy, located about 60 kilometres (37 mi) northwest of Milan and about 14 kilometres (9 mi) northwest of Varese. Duno borders the following municipalities: Brissago-Valtravaglia, Casalzuigno, Cassano Valcuvia, Cuveglio, Mesenzana, Porto Valtravaglia.