The authors agree that the surname may derive from the Latin personal name of Greek origin Milo (Milonis), an example of which is preserved in a deed of May 1061 of the Diplomatic Codex of Brescia. E. Rossoni notes that the surname shows two main areas: one in the region of Campania, between Naples and Salerno, and another in the Salento area —that is, the southernmost zone of the region of Puglia, in southern Italy—, with an area probably now extinct in Sicily. He adds that in some cases it could derive from a place name of Magna Graecia linked to the island of Milos, such as the locality Milo in the province of Catania, and documents traces of its fixing as a surname in the State Archive of Trapani, where in the register of 1440 a notary named Francesco Milo appears.

V. Blunda proposes instead a Germanic root: the personal name Milo as a hypocoristic form linked to the root mil, with the sense of "soft, sweet, gentle". He notes that Milo Crispin (~990–1048), Norman count of Évreux, was one of the first great lords of ducal Normandy, and warns that the popular association with Milo of Croton, the celebrated Greek athlete of the 6th century BC, constitutes a crossed etymology: the formal resemblance between the two traditions is the result of phonetic chance and not of a common origin.

The variants Milone and Milon are documented mainly in Campania, Sicily and Puglia, with the presence of Milon almost exclusive to southern Italy. Miloni, of very scarce occurrence, appears linked to Rome.