The authors agree that this surname derives from the old Roman nomen Aemilius, although they differ in the emphasis of their contributions. E. De Felice notes that the surname originated from the name Emilio —with the apocopated form Milio and the feminine variant Milia—, continuing the learned and ecclesiastical tradition of the Roman nomen Aemilius. He locates its presence in Friuli-Venezia Giulia.

E. Rossoni broadens the origin by linking it with the Gens Aemilia, a very ancient patrician family of Sabine origin already existing in the times of Romulus, which established itself in the Marche, Umbria, Abruzzo and Lazio area. According to Rossoni, the surname could derive directly from that lineage, from the Latin nomen Aemilius —which he associates with the meaning of "affable"— or from the Italian name Emilio. Rossoni places the surname mainly in the central strip of Italy that comprises the Marche, Umbria and Lazio, with specific zones also in Trieste and the Gorizia area. The variant Emiliozzi, on the other hand, is peculiar to the Macerata area.