E. Rossoni proposes that this surname could derive from a diminutive formed from the aphaeresis of the name Bonifacio, meaning "the one who has a good destiny" (from the Latin bonum fatum).

F. De Laurentiis offers two complementary hypotheses: on the one hand, he considers that Faccioli would be a northeastern variant of the surname Fazio, whose base is likewise the name Bonifazio or Bonifacio; on the other, he suggests that it could have originated in the nickname Facciolo, referring to people of a round and expressive face.

The surname presents multiple independent clusters of origin (ceppi), arisen in different regions without direct relation between them. According to Rossoni, Faccioli has specific zones in the west of the Veneto and the Brescia area, another in the Bologna area, and possibly also in Lombardy and Piedmont. The form Facciolini is typical of Abruzzo, in the area between the Teramo and Pescara areas. For its part, Facciolo presents a specific zone in the Padua area and another in the west of Calabria.