The authors agree that this surname derives from the medieval name Lombardo, formed from a nickname or appellative which between the 12th and 16th centuries had two values according to context. As a demonym, it designated the "inhabitant of, or native of, northern Italy (and in part also of the centre)". As an occupational name, especially in southern Italy and in the countries of western Europe, it alluded to the "merchant, banker, money-changer or usurer", activities carried on mainly by northern Italians and Tuscans.

E. De Felice notes that the surname is very frequent in Italy, with a marked presence in the north-west, in Tuscany and in Sicily. He adds that the variants Lombardelli predominate in Lombardy, and Lombardini in Tuscany.