The authors offer different readings of the origin of this surname. E. Rossoni notes that the surname is very widespread in Emilia-Romagna, in the Florence area, in the Piceno, in the Teramo, Perugia, L'Aquila, Frosinone and Rome areas, and in the Salento area —that is, the southernmost zone of the region of Puglia, in southern Italy. According to Rossoni, it could derive from the Roman Gens Lollia, or else from nicknames based on the Latin term lollium ("darnel", a weed), perhaps in allusion to unappealing characteristics of the ancestor.

P. Canè proposes instead an origin as a patronymic or given name, possibly derived from the Latin Julius, and regards the darnel hypothesis as less likely. F. De Laurentiis offers a different reading: he considers it a surname proper to the region of Campania, formed from the place name Lolli, in the Avellino area.

As for the variants, Rossoni indicates that Lollio is proper to the Bergamo area; Lollo shows one core in Veneto, another between the Frosinone and Latina areas, and another in those of Naples and Messina; while Lollia is practically non-existent.