Italian irredentism was a movement during the late 19th and early 20th centuries in Italy with irredentist goals which promoted the unification of geographic areas in which indigenous peoples were considered to be ethnic Italians.

Italian irredentism was not a formal organization but rather an opinion movement, advocated by several different groups, claiming that Italy had to reach its "natural borders" or unify territories inhabited by Italians to create a “Greater Italy”.

Italian ethnic regions claimed in the 1930s. Green: Nice, Ticino, Dalmatia, Malta, Corsica. Savoy and Corfu were also later claimed.