The authors agree that this surname derives from dialectal modifications of the aphaeresis of the name Giuseppe, referring to the ancestor who originated it. E. Rossoni notes, in addition, that 16th-century documents of the State Archive of Viterbo link it to a nickname related to the Latin term pipis, that is, "pepper." F. Miranda develops this same line for the Sicilian and southern lineage, indicating that Pepe would be the Italianization of the dialectal Pipi, with the figurative sense of someone "bold and of a strong, lively temperament," "spicy as pepper," according to the lexicographer Mortillaro.

As to geographic distribution, both authors agree that the surname is widely spread throughout the country, with a greater concentration in southern Italy. Miranda specifies that it has its main areas in Campania, Apulia, Lazio, Lombardy and Sicily, with a smaller presence in Piedmont, Basilicata, Tuscany, Calabria, Abruzzo, Emilia-Romagna, Liguria and Veneto. Rossoni adds that the derived forms show their own distributions: Pepi is concentrated in Tuscany, especially in the Florence, Siena and Grosseto areas; Peppe is typical of Lazio, with its main nucleus in Fondi; Peppetti appears in Todi, in the Perugia area; and Peppi, very rare, is located between the Bologna and Ravenna areas.