The authors agree that this surname belongs to southern Italy and derives from the base surname Ponte, forming part of a group of altered and hypocoristic forms that also includes Pontello, Pontèlli, Ponticiello, Ponticelli, Pontini and Pontoni. The common base is the place names formed on Ponte and Ponti, very diffused throughout Italy, which designate localities characterized by the presence of a bridge or their location beside one: among them, Ponticelli (Naples, Rieti), Pontiròlo Nuovo (Bergamo) and Ponte Alto (Belluno).

The suffix -illo is an affectionate diminutive proper to southern Italy, especially of Campania, Calabria and Apulia, and alludes to provenance from a place linked to a small bridge or to an ancestor associated with a locality called Ponte. R. Sgaramella documents the surname in Calabria, Basilicata and Lucera (Foggia), with the first known attestation in 1769 —A. Pontillo, of Foggia— and, in the variant Puntillo, in 1819, with Luigi Puntillo.