E. Rossoni notes that the surname would derive from the medieval Italian name Mastinus, documented in Verona in 1338. He records scattered areas of presence in the Oristano area —specifically at Milis, Bosa, Seneghe and Tresnuraghes— and in the Nuoro area —at Silanus, Macomer and Bolotana—, with a presence also in Cagliari.

A. Bongioanni considers that Mastino was a given name whose use came to be restricted to the Scaligeri. He notes, however, the existence in Sardinia of the surname Mastinu, which possibly had a nickname character in origin.