According to E. De Felice, Alessio is a patronymic surname derived from the personal name Alessio, which ultimately comes from the Late Latin forms Alexius and Alexis, adaptations of the Greek names Aléxios and Alexis. These names derive from the Greek verb aléxein, meaning “to defend” or “to protect,” giving the name the meaning of “defender” or “protector.” In some cases, it may also represent a shortened form of the Greek names Aléxandros or Aléxarchos.

De Felice notes that the basic form of the surname is widespread throughout Italy, while many of its variants are particularly characteristic of southern Italy.

F. De Laurentiis agrees with this etymology, emphasizing that the name means “defender” or “protector” and noting its broad distribution across the Italian peninsula.

P. Durante likewise identifies Alessio as a surname of Greek origin derived from the personal name, reflecting the long-standing tradition of forming hereditary surnames from given names.

Overall, Alessio is a surname of Greek origin derived from a personal name meaning “defender” or “protector,” originally identifying the descendants of an ancestor named Alessio.