Castelletto sopra Ticino, also referred to by locals as Castelletto Ticino or just Castelletto, is a comune in the Province of Novara in the Italian region of Piedmont, located about 100 km northeast of Turin and about 30 km north of Novara. Celtic inscriptions have been found. It is the birthplace of the immunologist Serafino Belfanti. It is also where singer Billy More is buried.