San Pietro Mosezzo is a comune (municipality) in the Province of Novara in the Italian region Piedmont, located about 80 kilometres (50 miles) northeast of Turin and about 5 kilometres (3 miles) west of Novara.

San Pietro Mosezzo is divided into four frazioni (wards)—San Pietro (chef-lieu), Cesto, Mosezzo and Nibbia—and three hamlets—Cascinazza, San Stefano and Torre San Pietrina (San Pietro Mosezzo's industrial park). The Canale Cavour flows across the town.

San Pietro Mosezzo borders the following municipalities: Biandrate, Briona, Caltignaga, Casaleggio Novara, Casalino, Novara, and Vicolungo.