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

According to the unreleased Fallout: Resource Wars, which was designed by J.E. Sawyer, the country fell into disarray by 2060, as the European Commonwealth dissolved, bickering and quarreling with its neighbors over the last few remaining resources on Earth. Northern Italy, in particular, was reduced to total anarchy.

Fallout
The Romans and their penchant for war are mentioned in the intro to the game.

Fallout 2
Flick from the Den speaks several Italian words and phrases, but it is unknown if he is actually of Italian descent or putting on an act.

Fallout 3

 * The Soil Stradivarius, pronounced swal, was created by Antonio Stradivari in Cremona.
 * In 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, and its leader based on Gaius Julius Caesar. 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 written by Antonio Vivaldi.

Fallout 4

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

Fallout 76

 * The pre-War restaurants Little Italy and Graviano's Italian Eatery are Italian-themed diners, the former having a picture of Rome's Colosseum on its logo.
 * In Wild Appalachia, the Pioneer Scout archaelogist exam contains questions about the history of Pompeii and Sicily.

Fallout Tactics
The Beretta 470 Silverhawk is of Italian origin.

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.

Fallout Pen and Paper D20
The Roman Empire is mentioned on the back of the game guide.

Fallout: Resource Wars
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.

Fallout: Brotherhood of Steel

 * The 9mm M9FS Beretta was manufactured by the Italian Fabbrica d'Armi Pietro Beretta firearms company.
 * The SPAS-12 was manufactured by the Italian Luigi Franchi società per azioni company.

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 76 and its update Wild Appalachia, Fallout Tactics, Fallout Shelter, Fallout: Brotherhood of Steel, Van Buren, and Fallout Pen and Paper d20.