E. Rossoni considers that this surname could derive from Italianizations of the Slavic patronymic or diminutive form Petrič, referring to the name Petrus. He notes that Petrizzi is extremely rare and specific to the area between the Salerno and Potenza areas, while its sister form Petrizzo is concentrated in the Salerno area —in localities such as Sassano, Padula, Olevano sul Tusciano and Monte San Giacomo—, with an additional presence in Campoformido, in the Udine area.

G. Rohlfs, on the other hand, proposes a Greek-Byzantine origin. For Rohlfs, Petrizzi is a sister form of Petrizzo, present in Lucania (Padula, Potenza, Sassano, Teggiano), and both function as hypocoristics of the Greek name Petros ('Peter'). As comparative support, he notes that in Greece the surname Petritzis survives.

The two proposals differ in their starting point: Rossoni points to an adaptation of the Slavic form Petrič, while Rohlfs refers directly to the Greek Petros, in keeping with the historical presence of Greek-Byzantine communities in southern Italy. Both authors agree, however, in noting the Salerno area and its surroundings —including localities of Basilicata— as the area of greatest rootedness of the surname.