E. Rossoni and N. Bergamo differ on the origin of the surname.

Rossoni suggests that all these forms derive from nicknames related to physical characteristics of the ancestor —especially the fact of having curly hair— or from their diminutive forms.

Rossoni distinguishes the variants: Rizza has an important area in Sicily (especially in the southern part), one in the Catanzaro and Crotone areas, and another in Lazio; Rizzi is very diffused in the north, with areas also in Apulia, Basilicata and Lazio; Rizzo is absolutely pan-Italian; Rizzoli has areas in the Bergamo area, in Trentino and in the Bologna and Parma areas; Rizzolo has a main area in Misilmeri (Palermo area), with areas also in Alessandria della Rocca (Agrigento area) and in Calabritto (Avellino area).

Bergamo, on the other hand, proposes a possible Greek origin, from the root rhiza ("root"), or else from the Latin rete, or from the term "curled."