Italianization (Italian: Italianizzazione; Croatian: talijanizacija; Slovene: poitaljančevanje; German: Italianisierung; Greek: Ιταλοποίηση) is the spread of Italian culture, people, or language, either by integration or assimilation.
It is most known for a process organized by the Kingdom of Italy to force cultural and ethnic assimilation, primarily, of the native populations living in the former Austro-Hungarian territories that were transferred to Italy after World War I in exchange for Italy having joined the Triple Entente in 1915. This process was conducted during the period of Fascist rule between 1922 and 1943.
Between 1922 and the beginning of World War II, the affected people were the German-speaking population of Trentino-Alto Adige, and Slovenes and Croats in the Julian March. The program was later extended to areas annexed during World War II, affecting Slovenes in the Province of Ljubljana, and Croats in Gorski Kotar and coastal Dalmatia, Greeks in the Ionian islands and, to a lesser extent, to the French- and Arpitan-speaking regions of the western Alps (such as the Aosta valley). On the other hand, the island of Sardinia underwent cultural and linguistic Italianization starting from an earlier period.
The former Austrian Littoral (later renamed the Julian March) was occupied by the Italian Army after the Armistice with Austria. Following the annexation of the March by Italy, 400 cultural, sporting (for example Sokol), youth, social and professional Slavic organizations, and libraries ("reading rooms"), three political parties, 31 newspapers and journals, and 300 co-operatives and financial institutions had been forbidden, and specifically so later with the Law on Associations (1925), the Law on Public Demonstrations (1926) and the Law on Public Order (1926), the closure of the classical lyceum in Pazin, of the high school in Volosko (1918), the closure of the 488 Slovene and Croat primary schools followed.
The period of violent persecution of Slovenes in Trieste began with riots in 13 April 1920, which were organized as a retaliation for the assault on the Italian occupying troops by the local Croatian population in the 11 July Split incident. Many Slovene-owned shops and buildings were destroyed during the riots, which culminated in the burning down of the Narodni dom ("National House"), the community hall of the Triestine Slovenes, by a group of Italian Fascists, led by Francesco Giunta,. Benito Mussolini praised this action as a "masterpiece of the Triestine fascism". Two years later he became prime minister of Italy.
In September 1920, Mussolini said:
When dealing with such a race as Slavic - inferior and barbaric - we must not pursue the carrot, but the stick policy. We should not be afraid of new victims. The Italian border should run across the Brenner Pass, Monte Nevoso and the Dinaric Alps. I would say we can easily sacrifice 500,000 barbaric Slavs for 50,000 Italians.
Italian teachers were assigned to schools and the use of Croatian and Slovene languages in the administration and in the courts restricted. After March 1923 these languages were prohibited in administration, and after October 1925 in law courts, as well. In 1923, in the context of the organic school reform prepared by the fascist minister Giovanni Gentile, teaching in languages different from Italian was abolished. In the Julian March this meant the end of teaching in Croatian and Slovenian. Anyway, in Šušnjevica (it: Valdarsa) the use of Istro-Rumanian language was granted since 1923.
In 1926, claiming that it was restoring surnames to their original Italian form, the Italian government announced the Italianization of German, Slovene and Croat surnames. In the Province of Trieste alone, 3,000 surnames were modified and 60,000 people had their surnames amended to an Italian-sounding form. First or given names were also Italianized.
Slovene and Croat societies and sporting and cultural associations had to cease every activity in line with a decision of provincial Fascist secretaries dated 12 June 1927. On a specific order from the prefect of Trieste on 19 November 1928, the Edinost political society was also dissolved. Croat and Slovene financial co-operatives in Istria, which at first were absorbed by the Pula or Trieste savings banks, were gradually liquidated.
In 1927, Giuseppe Cobolli Gigli, the minister for public works in fascist Italy, wrote in Gerarchia magazine, a Fascist publication, that "The Istrian muse named as Foibe those places suitable for burial of enemies of the national [Italian] characteristics of Istria".
The Slovene militant anti-Fascist organization TIGR emerged in 1927. It co-ordinated the Slovene resistance against Fascist Italy until its dismantlement by the Fascist secret police in 1941. At the time, some TIGR ex-members joined the Slovene Partisans.
During World War II, Italy occupied almost all of Dalmatia, and the Italian government made stringent efforts to Italianize the region. Italian occupying forces were accused of committing war crimes in order to transform occupied territories into ethnic Italian territories.
The Italian government operated concentration camps for Slavic citizens, such as Rab concentration camp and one on the island of Molat. Survivors received no compensation from Italy after the war.
Mario Roatta was the commander of the Italian 2nd Army in Yugoslavia. To suppress the mounting resistance led by the Slovene partisans, he adopted tactics of "summary executions, hostage-taking, reprisals, internments and the burning of houses and villages." After the war the Yugoslav government sought unsuccessfully to have him extradited for war crimes from Spain, where he was protected by Francisco Franco.  Mario Robotti issued an order in line with a directive received from Mussolini in June 1942: "I would not be opposed to all (sic) Slovenes being imprisoned and replaced by Italians. In other words, we should take steps to ensure that political and ethnic frontiers coincide."
In 1919, at the time of its annexation, the southern part of Tyrol was inhabited by almost 90% German speakers. In October 1923, the use of the Italian language became mandatory (although not exclusive) on all levels of federal, provincial and local government. Regulations by the fascist authorities required that all kinds of signs and public notices had to be in Italian only. Maps, postcards and other graphic material had to show Italian place names. In September 1925, Italian became the sole permissible language in courts of law. Illegal Katakombenschulen ("Catacomb schools") were set up by the local German-speaking minority to teach children the German language. The government created incentives to encourage immigration of native Italians to the South Tyrol.
Several factors limited the effects of the Italian policy, namely the adverse nature of the territory (mainly mountains and valleys of difficult access), the difficulty for the Italians from southern Italy to adapt to a completely different environment and, later on, the alliance between Germany and Italy. Under the 1939 South Tyrol Option Agreement, Adolf Hitler and Benito Mussolini determined the status of the German people living in the province. They either had to opt for emigration to Germany or stay in Italy and become fully Italianized. Because of the outbreak of World War II, this agreement was never fully implemented and most ethnic Germans remained or returned at the end of the war.
The cultural remnants of the Venetian period were Mussolini's pretext to incorporate the Ionian Islands into the Kingdom of Italy. Even before the outbreak of World War II and the Greek-Italian 1940-1941 Winter War, Mussolini had expressed his wish to annex the Ionian Islands as an Italian province. After the fall of Greece in early April 1941, the Italians occupied much of the country, including the Ionians. Mussolini informed General Carlo Geloso that the Ionian Islands would form a separate Italian province through a de facto annexation, but the Germans would not approve it. Nevertheless, the Italian authorities continued to prepare the ground for the annexation. Finally, on 22 April 1941, after discussions between the German and Italian rulers, Hitler agreed that Italy could proceed with a de facto annexation of the islands. Thus on 10 August 1941 the islands of Corfu, Cephalonia, Zakynthos, Lefkada and some minor islands were officially annexed by Italy as part of the Grande Communità del Nuovo Impero Romano (Great Community of the New Roman Empire). 
As soon as the fascist governor Piero Parini had installed himself on Corfu he vigorously began a forced Italianization policy that lasted until the end of the war. The islands passed through a phase of Italianization in all areas, from their administration to their economy. Italian was designated the islands' only official language; a new currency, the Ionian drachma, was introduced with the aim to hamper trade with the rest of Greece, which was forbidden by Parini. Transportation with continental Greece was limited; in the courts, judges had to apply Italian law, and schooling followed the educational model of the Italian mainland. Greek administrative officials were replaced by Italian ones, administrative officials of non-Ionic origin were expelled, the local gendarmes were partially replaced by Italian Carabinieri, although Parini initially allowed the Greek judges to continue their work, they were ultimately replaced by an Italian Military Court based in Corfu. The "return to the Venetian order" and the italianization as pursued by Parini were even more drastic than the italianization policies elsewhere, as their aim was a forced and abrupt cessation of all cultural and historical ties with the old mother country. The only newspaper on the islands was the Italian language "Giornale del Popolo". By early 1942 pre-war politicians in the Ionian Islands began to protest Parini's harsh policies. Parini reacted by opening a concentration camp on the island of Paxi, to which two more camps were added on Othonoi and Lazaretto islands. Parini's police troops arrested about 3,500 people, which were imprisoned at these three camps. The Italianization efforts in the Ionian islands ended in September 1943, after the armistice of Cassibile.
Since 1720, the island of Sardinia had been an overseas possession of the House of Savoy, which at the time already controlled a number of other states in Italy, most notably Piedmont. The Savoyards imposed the Italian language on Sardinia as part of a wider cultural policy designed to bind the island to the Mainland in such a way as to prevent either future attempts of political separation, based on the language native to the islanders, or curb a renewed interest on the part of Spain. However, it was not until the rise of fascism that Sardinian was actively banned and/or excluded from any residual cultural activities to enforce the shift to Italian. By the end of the second World War, Italian had become the island's main language. Within a few generations Sardinian, as well as Alghero's own Catalan dialect, would become a minority language spoken by fewer and fewer Sardinian families, the majority of whom now use only Italian as their everyday language.