The surname Benzo and its variants —such as Penzo, Benzi, Penza or Pensa— are spread in northern Italy and in Tuscany, with particular intensity in areas such as Venice for Penzo. According to E. De Felice, its origin goes back to personal names of Germanic root such as Bènzo and Pènzo, documented as early as the Early Middle Ages. These forms derive from a hypocoristic of compound names with the element bandwo- ("standard", "insignia", "banner"), which suggests an origin linked to military or symbolic traditions. He also notes that in some cases, such as Bènzi in Tuscany, they may reflect regional phonetic adaptations of other variants such as Bènci.

Along the same lines, F. De Laurentiis confirms the wide diffusion of the surname in the north and in Tuscany, and agrees on its Germanic base, linked to the idea of "vessillo" or insignia. This interpretation reinforces the anthroponymic character of the surname, derived from personal names that evoked symbols of identity or belonging, frequent in the medieval Germanic tradition.

For its part, the tradition gathered in sources from Alessandria stresses the Germanic origin and Frankish tradition of the surname, indicating that Benzo may be an abbreviated form derived from bandwa, although it also considers the possibility of a base in the name Benno, likewise of Germanic origin. It also highlights its early historical documentation, as in the pact of defence between Alessandria and Genoa in 1192. Taken together, the various interpretations agree in pointing to an old and prestigious origin, linked to personal names of Germanic root that evolved into various regional forms over time.