Piuro (Piür in the local dialect) is a comune (municipality) in the Province of Sondrio in the Italian region Lombardy, located about north of Milan and about northwest of Sondrio, on the border with Switzerland. As of 31 December 2004, it had a population of 1,938 and an area of .
The municipality of Piuro contains the frazione (subdivision) Savogno.
Piuro borders the following municipalities: Avers (Switzerland), Campodolcino, Chiavenna, Ferrera (Switzerland), Madesimo, Novate Mezzola, Prata Camportaccio, San Giacomo Filippo, Soglio (Switzerland), Villa di Chiavenna.
On 4 September 1618, Piuro (then belonging to the Three Leagues) was the site of one of the worst landslides in recorded history. The event, described as an avalanche (somewhat inaccurately as it was more probably a mudslide), completely wiped out Piuro and killed between 1,000 and 2,500 people.