The authors agree that this is a surname of Sicilian origin and dialectal character, linked to the religious condition of the person. Its etymon is the Sicilian word vattiatu (also recorded as vattiato), meaning "baptised" or "converted", used to designate the Christian state in contrast to non-Christians.

V. Blunda notes that, as a surname, it may have originated in a nickname applied to the convert from Judaism or Islam to Christianity, a frequent situation in medieval Sicily, especially after the Christian unification of the island under the Normans and the processes of forced conversion of the Jewish communities from the 15th century. He adds that the variant Vattiato preserves the dialectal spelling with an initial v-.

F. Miranda also proposes a second hypothesis of origin: the place name Sant'Agata Li Battiati, a locality in the province of Catania, whose name would derive from a church built in 1635 in honour of Saint Agatha, to which the inhabitants went for baptisms, being known as the church of Sant'Agata li vattiati; the name would then have extended to the whole locality. Miranda also indicates that the surname is found mainly in the Catania area, and to a lesser extent in the Messina, Enna, Syracuse and Ragusa areas.