Sondalo (Sondel in Valtellinese dialect) is a comune (municipality) in the Province of Sondrio in the Italian region Lombardy, located about northeast of Milan and about northeast of Sondrio.
Sondalo borders the following municipalities: Grosio, Ponte di Legno, Valdisotto, Valfurva, and Vezza d'Oglio.
Sondalo is home to the E. Morelli Hospital, a 3000-bed facility formerly run as a tuberculosis sanitarium.