F. De Laurentiis notes that the surname is spread in southern Italy and that its base is the name Fazio or Faccio, an aphaeretic hypocoristic of Bonifazio or Bonifacio, documented from the 12th century under the forms Fatius, Fazius, Facius and Faciolus. Its transformation into a surname is attested in Venice towards 1261-1262, with the record "Angelo Facio".

F. Miranda agrees on the origin from the medieval name Fatius, an aphaeretic hypocoristic of Bonifazio, but specifies its etymology: the name derives from the Latin bonum ("good") and fatum ("destiny"), with an augural function by which the parents wished a good destiny for their children. Miranda adds that the surname also appears in many Italian regions as a patronymic preceded by di or de, giving rise to the forms Di Fazio and De Fazio.

G. P. Holmes agrees that the surname derives from the abbreviation of Bonifazio, although he defines it only as "the one who does good", an interpretation that departs from the more precise Latin etymology offered by Miranda.

The surname has presence in different regions of Italy, with greater concentration in Sicily and Calabria, and is also frequent in Lombardy, Liguria, Lazio, Puglia and Piedmont.