The scholars consulted agree that this surname derives from the Late Latin personal name Gregorius, an adaptation of the Greek Gregorios, formed on the verb gregorein ("to be awake, alert"), with the original meaning "awake, quick, intelligent." Its spread throughout the Middle Ages was driven by the prestige of saints and Church Fathers such as Gregory of Nyssa and Gregory of Nazianzus, and especially by Pope Gregory the Great.

E. De Felice notes that in some areas along the Adriatic coast and in southern Italy the surname may continue directly the modern Greek and Byzantine name, pronounced grigori(o), a pronunciation that would explain the variants with Gri-. He further observes that apocopated forms and variants in -ich/-ic and -ato/-atto are more frequent in northeastern Italy, while in the south patronymics with De- or Di- appear, along with forms such as Gregorace, Gligori, and Grivori, characteristic of Calabria. The abbreviated form Gori is common throughout central and northern Italy.

E. Rossoni specifies that the form Gregori is found throughout central and northern Italy, while Gregorio shows, besides a presence in the north, a main concentration in Campania, especially in the area of Salerno, with additional presences in the area of Bari, in the area of Potenza, and in Sicily, above all in the area of Messina.