Quarna Sotto is a comune (municipality) in the Province of Verbano-Cusio-Ossola in the Italian region Piedmont . It is located about 100 kilometres (62 mi) northeast of Turin and about 15 kilometres (9 mi) southwest of Verbania.

Quarna Sotto borders the following municipalities: Nonio , Omegna , Quarna Sopra , Valstrona, Varallo Sesia.