1940

10 June - Italy declares war against France and the United Kingdom, beginning the African and Southern European theatres of WWII.

1941

27 November - The Battle of Gondar ends in an Allied victory, Italian East Africa is occupied by the Allies.

1943

13 May - The Italo-German army surrenders at Tunisia, losing the African continent to the Allies.

9 July - Operation Husky, the Allied invasion of Sicily, commences as Allied US-British forces land in Southern Sicily.

24 July - The Grand Council of Fascism is summoned by Mussolini for the first time since the war, ending in a 19-8 vote for King Victor Emmanuel III to dismiss Mussolini.

25 July - As per the order the day prior, the King dismisses and arrests Mussolini, he is eventually imprisoned at Gran Sasso in Abruzzo. The King appoints Marshal Pietro Badoglio as Prime Minister of Italy, the first change in the position since 1922. This date is historically known as the end of the fascist regime in Italy (il 25 Luglio).

5 August - The Chamber of Fasces and Corporations, the lower house of the Parliament of the Kingdom of Italy, officially disbands. It is replaced by the Chamber of Deputies of the Kingdom of Italy.

17 August - Operation Husky ends in an Allied victory - with the Allied occupation of Sicily, forcing Italian and German troops to retreat to the Italian peninsula.

3 September - Italy signs the Armistice of Cassibile, forcing Italy out of the war.

8 September - Germany commences "Operation Axis", an operation to invade Italy from the North and disarm the Italian Army. Responding to the German invasion, several ideologically opposing forces within Italy unite and form the National Liberation Committee (CLN) and begin actively resisting the German army through a campaign of guerilla warfare primarily in Northern Italy. The King, alongside pro-royal and republican Italian figures, flee to Southern Italy and establish a pro-Allied rival government. This effectively begins the Italian Civil War.

12 September - Germany frees Mussolini from prison during the Gran Sasso Raid.

23 September - Operation Axis ends with the German army invading the Italian peninsula up to Calabria. Germany simultaneously establishes the Italian Social Republic (RSI) with Mussolini as de jure leader.

15 December - "Christian Democracy", a centrist, anti-fascist, Christian-democratic party in Italy, is allegedly founded in the RSI on this date.

1944

8 June - The CLN and the Allies agree to allow Ivanoe Bonomi to become Prime Minister, taking Pietro Badoglio's place.

18 June - Bonomi is sworn in as Prime Minister of Italy.

29 December - Alcide De Gasperi becomes the Secretary of Christian Democracy.

1945

28 April - Mussolini is executed, seemingly by Italian partisans. His body, alongside the body of his mistress Clara Petacci, are strung up at Piazzale Loreto in Milan.

29 April - German forces in Italy and the RSI formally surrender to the Allies at Caserta, dissolving the RSI and ending the Italian front of WWII.

2 May - The date which is potentially recognised as the end of the Italian Civil War, synomymous with the end of WWII in Europe.

21 June - Ferrucio Parri is sworn in as Prime Minister of Italy, replacing Ivanoe Bonomi.

22 June - An alternative, equally possible date for the end of the Italian Civil War, synonymous with the Togliatti Amnesty, an effort by Italian Communist (and then Minister of Justice) Palmiro Togliatti to provide amnesty and reduced punishment for Italian fascists and partisans during the Civil War and before.

10 December - Alcide De Gasperi is sworn in as Prime Minister of Italy, replacing Ferrucio Parri. He leads a coalition government made up of Christian Democracy (DC), the Italian Communist Party (PCI), the Italian Socialist Party (PSI), the Italian Republican Party (PRI), the Italian Liberal Party (PLI), and the Action Party (PdA).

1946

9 May - Victor Emmanuel III formally abdicates his throne, leaving his son, Umberto II, as King of Italy.

2 June - The 1946 Italian Institutional Referendum takes place, having Italians decide if they would rather live under a monarchy or a republic. The referendum ends with a majority (54.27%) of Italians voting in favour of Italy becoming a republic. Simultaneously, the Chamber of Deputies of the Kingdom of Italy officially disbands.

2-3 June - The 1946 Italian General Election takes place, technically the last election during the Kingdom of Italy and the first general election since the end of the Fascist regime. Christian Democracy wins the election by plurality with 35.21% of the vote, Alcide De Gasperi remains as Prime Minister.

11 June - The Via Medina Massacre at Naples occurs, where an altercation between monarchists and Italian Communist Party (PCI) members occurred near a bombing that resulted in 9 deaths and >100 injuries at Via Medina. The monarchists were the victims of the attack, but the actual perpetrators of the bombing is unknown.

12 June - The position of King of Italy formally ends as Umberto II abdicates his throne as King of Italy. He is the last to be King.

13 June - De Gasperi assumes the position of the "Acting President of the Republic", at the time, the position was known as the "Provisional Head of State of Italy", but De Gasperi himself did not receive this title, and only had the powers of the title.

18 June - The Supreme Court of Cassation meets to formally proclaim the results of the referendum, essentially ending the Kingdom of Italy as a political entity, and beginning the history of the Italian Republic. Simultaneously, the Parliament of the Kingdom of Italy officially disbands as an institution.

25 June - The Constituent Assembly is formed as a unicameral body, replacing the Parliament of the Kingdom of Italy. Simultaneously, De Gasperi becomes a member of the Constitutent Assembly.

1 July - De Gasperi hands over the powers of the Provisional Head of State of Italy to Enrico De Nicola, officially receiving the title. As of 2026, he becomes the only Italian political figure to have officially received the title.

16 July - De Gasperi resigns as Secretary of Christian Democracy.

18 August - The Vergarola Massacre at Pola (now Pula), Istria occurs, where the sudden detonation of explosives resulted in >100 deaths and 100 injured at Vergarola beach. The exact nature on who or what detonated the explosives still remains unknown, with the Allied Military Authorities, governing Pola at the time, only concluding that the explosion was indeed deliberate.

1947

10 February - The Treaty of Paris between Italy and the Allied Powers is signed between Italy and the Allies, which includes, but is not limited to the:

• Ceding of several areas at the Italo-French border to France;
• Ceding of Istria and Fiume to Yugoslavia (much of the area is known as the Julian March);
• Ceding of Trieste as an independent Free City (also part of the Julian March);
• Renunciation of Italian claims in Africa;
• Formal dissolution of the Italian Empire;
• Banning of fascist organisations, political or military or semi-military in Italy (art 17); and
• Demolition of many military installations.

20 April - The 1947 Sicilian Regional Election takes place, the first such election of the Sicilian Parliament. The communist "People's Bloc", made up of the PCI, PSI, PdA, win the election by plurality with 30.4% of the vote, gaining 29 seats.

1 May - The Portella della Ginestra Massacre in Piana degli Albanesi, Sicily occurs, where Sicilian separatists targeted and killed communist Sicilian peasantry, resulting in 11 deaths and 27 injuries.

31 May - De Gasperi expels all Communist and Socialist members from his cabinet. This was a decision taken under apparent pressure from the United States as a prerequisite for receiving economic aid.

22 June - The Partinico Massacre at Partinico, Sicily occurs, where bandits attacked a "Chamber of Labour" (i.e. a union type headquarters), resulting in 2 deaths and 3 injuries.

15 September - The Treaty of Paris (1947) formally comes into effect, causing Italy to lose all the aforementioned claims, and Trieste to break away from Italy under the name "the Free Territory of Trieste".

22 December - The Italian Constitution is officially ratified by the Constituent Assembly (453 votes in favour, 62 against), officially declaring Italy a unitary parliamentary constitutional republic.

28 December - The PCI and PSI form a coalition named the "Popular Democratic Front" (FDP) ahead of the 1948 general election.

1949

24 August - Italy joins the North Atlantic Treaty Organization (NATO) as a founding member.

29 October - The Melissa Massacre occurs at Melissa, Calabria, where police shot at demonstrating peasantry, resulting in 3 deaths and 15 injuries.