Castro (Bergamasque: ) is a comune (municipality) in the Province of Bergamo in the Italian region of Lombardy, located about northeast of Milan and about northeast of Bergamo on the western side of the lake Iseo. As of 31 December 2019, it had a population of 1,292 and an area of .
Castro borders the following municipalities: Lovere, Pianico, Pisogne, Solto Collina.