The scholars consulted agree that this surname derives from the term giudice ("judge"), which in the Middle Ages designated officials invested with functions that were not only judicial but also political, administrative, and military.

E. De Felice notes that the forms iudice and iodice are southern variants of the same term. He adds that Giudice and Giudici also constitute a surname of Jewish tradition, in which case they represent the modern translation of the Hebrew personal name Dayyan, meaning "judge" in the sense of "religious and political-military leader" of the ancient people of Israel, with a documented presence in Trieste and, sporadically, in other regions.

E. Rossoni broadens the motivation of the surname by noting that the founding ancestor may have held the office of judge or served under one. Regarding geographical distribution, he indicates that Giudice is predominantly southern Italian, with its main concentration in southern Sicily, while Giudici has independent origins in different regions: one stock consolidated in the area of Lombardy, and possible isolated pockets in Piedmont, Genoa, Tuscany, and Lazio.

It is also recorded that this is one of the more widespread Italian surnames, carrying the meaning of "judge" or "justice."