San Possidonio (Mirandolese: ) is a comune (municipality) in the Province of Modena in the Italian region Emilia-Romagna, located about northwest of Bologna and about northeast of Modena.
San Possidonio borders the following municipalities: Cavezzo, Concordia sulla Secchia, Mirandola, Novi di Modena.
San Possidonio is twinned with: