The authors agree that this surname and its variants derive from the name of the nation Spain or from its ethnic name, indicating a Spanish origin or some connection with that country. In some cases they may indicate a direct provenance, as happened with the Sephardic Jews expelled from Spain in 1492, who settled in various areas of the Italian peninsula.

E. Rossoni documents cases of the surname in Sant'Egidio, in the Salerno area, from 1520. He notes that Spagna, rare, appears scattered throughout Italy; that Spagnoli is very widespread in the centre-north; and that Spagnolo is concentrated in Veneto, Calabria, Campania and Apulia. The variant Spagnuolo extends across the whole of southern Italy, while Spagnulo has a secondary area in Salerno and its main area around Taranto.

E. De Felice specifies that Spagnol is typical of northern Italy, and that Spagnul corresponds to the Friuli-Venezia Giulia region. Rossoni, for his part, locates Spagnol specifically in the provinces of Treviso and Pordenone. Both authors agree that the forms Spagnolo and Spagnuolo —the latter with the Neapolitan dialectal variant— are especially frequent in Campania and Calabria.