Commessaggio (Mantovano: Cumsas) is a comune (municipality) in the Province of Mantua in the Italian region Lombardy, located about 120 kilometres (75 mi) southeast of Milan and about 25 kilometres (16 mi) southwest of Mantua.

The municipality of Commessaggio contains the frazione (subdivision) Bocca Chiavica.

Commessaggio borders the following municipalities: Gazzuolo, Sabbioneta, Spineda, Viadana.

Demographic evolution