The authors differ on the etymology of this surname. E. Rossoni proposes that it would derive, also through hypocoristic or pejorative forms, from the Germanic name Giro, Gironis, in turn from the medieval Germanic term gir, with the meaning "spear". F. De Laurentiis, by contrast, holds that the base would be a nickname applied to someone who moved from place to place, stopping only temporarily: that is, a vagrant or wanderer.

As for geographical distribution, Rossoni notes that the surname has multiple independent clusters of origin (ceppi), arisen in different regions without direct relation between them. Giri appears in isolated pockets of Piedmont, specifically in the Turin and Cuneo areas, between the Verona and Rovigo areas, in the Macerata area and in Rome. Derived forms such as Girini and Girino are concentrated in Piedmont and in Rome; Giro is typical of Veneto; Gironacci is proper to the Marche; Girone is present in Genoa, Rome, the Caserta area, the Naples area, Bari and Messina; and Gironi appears in the Milan, Verona, Bologna, Florence, Arezzo and Rome areas.