Italy

Italy officially the Italian Republic was a country in Europe before the Great War.

Background
During World War II, Italy fought on the side of the Axis Powers under the leadership of the dictator Benito Mussolini. His regime quickly fell, and the country surrendered to allied forces after a crushing defeat. Italy's affairs after 1945 are unknown, due to the divergence. Most likely, the modern Italian Republic was established directly following the war.

By 2060, as the European Commonwealth dissolved, the country fell into disarray, bickering and quarreling with its neighbors over the last few remaining resources on Earth. Northern Italy, in particular, was reduced to total anarchy.

Italy was also the headquarters of the renowned firearms manufacturer Beretta.

Fallout 3

 * The Soil Stradivarius was created by Antonio Stradivari in Cremona.
 * In the add-on Point Lookout, the pre-War Colontoni's Pizzeria bears an Italian flag on the building (The flag has inverted colors).

Fallout: New Vegas

 * Caesar's Legion, a major organization in the southwestern United States, based their culture and society on Ancient Rome, an old Italic civilization. The city of Rome and the Rubicon river are also referenced. The historic European region known as Gaul is mentioned as well, which encompassed parts of Northern Italy.
 * The Ultra-Luxe plays music from Antonio Vivaldi.

Fallout 4

 * Sal Barsconi, a pre-War mob boss, was of Italian descent.
 * In the add-on Vault-Tec Workshop, The Sicilian espresso machine refers to the island of Sicily and the origination of espresso from Italy.

Fallout Shelter
The republic robes are based on the Roman Republic.

Van Buren
The three Giordano brothers of Hoover Dam who run 3-Some Caravan are of Italian descent.

Appearances
References to Italy, such as mentions, Italian products, and associated people appear in Fallout, Fallout 2, Fallout 3 and its add-on Point Lookout, Fallout: New Vegas and all its add-ons, Fallout 4 and its add-on Vault-Tec Workshop, Fallout Tactics, Fallout Shelter, Fallout: Brotherhood of Steel and Van Buren.

The plot of J.E. Sawyer's hypothetical Fallout: Resource Wars game would involve a crew of soldiers from the Royal Armoured Corps who become stranded in a war-torn anarchistic northern Italy and have to fight their way to the English Channel in a bunch of quickly degrading vehicles, scavenging replacements, fuel, and weapons as they go.