Castelletto sopra Ticino, also referred to by locals as Castelletto Ticino or just Castelletto, is a comune (municipality) in the Province of Novara in the Italian region of Piedmont, located about northeast of Turin and about north of Novara. Celtic inscriptions have been found.
It is the birthplace of the immunologist Serafino Belfanti and the 1930s athlete Mario Lanzi, here died Vittorio Seghezzi, racing cyclist, and Aleardo Terzi, illustrator and artist. It is also where singer Billy More is buried.
In Castelletto sopra Ticino there's the medieval Visconti Castle, named after the Visconti houe, to which it belonged between the 13th and 20th centuries.