The surname Banfi presents a multiple origin, with interpretations that vary according to the geographical area. According to E. Rossoni, in Tuscany it could be linked to the noble Banfi family, whose name was given to a castle in Montepulciano. This hypothesis suggests a toponymic origin linked to an aristocratic lineage, where the surname is directly associated with a place identified by the family.

In the case of Lombardy —where the surname presents its greatest concentration—, E. Rossoni proposes a different derivation, linked to a dialectal nickname based on the verb banfà, meaning "to be out of breath". In this sense, the surname would have arisen as a descriptive trait applied to a person, in line with the formation of many medieval surnames from physical characteristics or behaviours.

For his part, F. De Laurentiis introduces a third possibility, noting that the surname may have as its base the Pugliese place name Banfi. This interpretation reinforces the idea of a geographical origin in some cases. Taken together, the various perspectives show a surname of complex formation, which may have arisen independently in different regions, whether from a noble lineage, a dialectal nickname or a place name.