Chiuro (Lombard: Ciür) is a comune (municipality) in the Province of Sondrio in the Italian region of Lombardy, located about 100 kilometres (62 mi) northeast of Milan and about 9 kilometres (6 mi) east of Sondrio, on the border with Switzerland. As of 31 December 2004, it had a population of 2,499 and an area of 51.8 square kilometres (20.0 sq mi).

The municipality of Chiuro contains the frazioni (subdivisions, mainly villages and hamlets) Castionetto and Casacce.

Chiuro borders the following municipalities: Brusio (Switzerland), Castello dell'Acqua, Lanzada, Montagna in Valtellina, Ponte in Valtellina, Poschiavo (Switzerland), Teglio.