The authors agree that this surname derives from the Latin porta ("entrance, passage, access") and designated originally those who lived near the gate of a city or a borough. It is, therefore, a surname of a toponymic-locative origin, arisen from bynames that identified people or family groups by their habitual place of residence within the urban space.

F. De Laurentiis notes that the surname is diffused throughout Italy, with a greater frequency in Liguria, and that it was formed from nicknames and descriptive designations applied to those who lived near a gate of the city or the village. R. Brondolo agrees in highlighting its presence especially in Lombardy and Liguria. E. Rossoni adds that the first records of its transformation into a surname are found in Portovaltravaglia, in the Varese area, from the 15th century, and that its distribution also covers specific pockets in the region of Campania, Apulia and central-southern Sardinia.