The authors agree that the surname derives from the Latin cognomen Marullus, documented from the time of Caesar's death and subsequently in the age of Augustus.

E. Rossoni notes that the earliest traces of its fixing as a surname are recorded around the 16th century in Messina. Rossoni further distinguishes between two forms: Marulli, which appears to be proper to the region of Puglia, with possible pockets in the Chieti area and in the Palermo area; and Marullo, which shows several independent origins in different regions of southern Italy: in Sicily, in the Catanzaro area, in the Salento area —that is, the southernmost zone of the region of Puglia— and in the Naples area.

F. De Laurentiis proposes, for his part, an alternative etymology and derives the surname from mares, without specifying the linguistic origin or the context of that form.