E. Rossoni proposes that this surname would derive from alterations of the Italianization of the Germanic name Wido, that is, from a variant of the medieval Italian name Guido, probably borne by the founding ancestors. According to Rossoni, Guitti has a presence in Brescia and in the Ravenna and Ferrara areas, while the form Guitto appears in the Naples area, in localities such as Pozzuoli and Giugliano di Campania.

F. De Laurentiis proposes, by contrast, a different base: the nickname or appellative guitto, which in Italian designated a low-grade actor, generally itinerant, and by extension a mean person who lived in a wretched and slovenly way. On this reading, the surname would have arisen as a descriptive byname before becoming a surname.