E. De Felice and V. Blunda differ on the origin of the surname.

De Felice derives it from the personal name of Germanic origin Adelferio and, in syncopated form, Alferio, documented from the 9th century in the south and from the 12th in the north in the Latinised forms Adelferius (Benevento, 839) and Alferius (Genoa, 1133).

De Felice specifies that the tradition is Frankish. The first element is athala- ("noble, nobility of lineage"), and the second fara-, or, as a nomen agentis, faraz, from the verb faran ("to travel, to move"; German fahren), with the sense of "to lead, to guide an expedition". The original meaning could therefore be "the one who is in command by nobility".

De Felice considers the hypothesis of a derivation from alfiere ("standard-bearer"), from Old Spanish alfiéreç, modern alférez, from the Arabic al-fāris ("horseman"), to be contradicted by the antiquity of the name: the term alfiere is documented only from the 16th century, and to this is added the form Adelferio. He clarifies that only in Sicily might the very rare surname Alfieri have as its base alfièri, a direct loan from Spanish into Sicilian.

De Felice notes that it is widespread throughout peninsular Italy in the fundamental form. Alfero is peculiar to Piedmont; Aufiero, Aufieri, Alfèrio, Alfè and Arfè are peculiar to the Naples area, where al- before a consonant can become au- and ar-.

Blunda, for the Sicilian variant, derives it from the Arabic etymon al fāris ("the knight, the horseman"), a title that designated high-ranking warriors in the Islamic world and that also passed into the Romance languages as "alférez" (officer who carries the standard). He identifies it as one of the most representative surnames of the onomastic legacy of the Emirate of Sicily (827–1091).