Campione d'Italia (Italian: [kamˈpjoːne diˈtaːlja]; Comasco: Campiùn [kamˈpjuŋ]) is a comune (municipality) of the Province of Como in the Italian region of Lombardy. Located on the shores of Lake Lugano, it is an enclave surrounded by the Swiss canton of Ticino. At its closest, the enclave is less than one kilometre (0.6 mi) from the rest of Italy, but the intervening mountainous terrain requires a journey by road through the Swiss village of Bissone of over 14 km (9 mi) to reach the nearest Italian town, Lanzo d'Intelvi, and over 28 km (17 mi) to reach the city of Como. The comune's population was 1,748 in 2021.

In the first century BC, the Romans founded the garrison town of Campilonum to protect their territories from Helvetii invasions.

In 777, Toto of Campione, a local Lombard lord, left his inheritance to the archbishopric of Milan. Ownership was transferred to the abbey of Sant’Ambrogio. In 1512, the surrounding area of Ticino was transferred from the ownership of the bishop of Como to Switzerland by Pope Julius II, as thanks for the support in the War of the Holy League. However, the abbey maintained control over what is now Campione d'Italia and some territory on the western bank of Lake Lugano.

When Ticino chose to become part of the Swiss Confederation in 1798, the people of Campione chose to remain part of the Cisalpine Republic. In 1800, Ticino proposed exchanging Indemini for Campione. In 1814 a referendum was held, and the residents of Campione opposed it. In 1848, during the First Italian War of Independence, Campione petitioned Switzerland for annexation.^{[citation needed]} This was rejected due to the Swiss desire for neutrality.

After Italian unification in 1861, all land west of Lake Lugano and half of the lake were given to Switzerland so that Swiss trade and transport would not have to pass through Italy. The d'Italia was added to the name of Campione in the 1930s by the regime of Italian dictator Benito Mussolini, making the name translatable to "Champion of Italy", and an ornamental gate to the village was built. This was to assert the enclave's Italian character.

During World War II, the US Office of Strategic Services (OSS – the precursor to the CIA), partly through Berne OSS chief Allen Welsh Dulles, maintained a unit in Campione for operations in Italy. At the time the Italian fascist regime did not have control over the enclave. The Swiss ignored the situation as long as the Americans kept a low profile. Postage stamps were issued during this period inscribed "Campione d'Italia" and valued in Swiss currency.

The population of the enclave according to the Italian census was:

Campione has had a considerable amount of economic and administrative integration with Switzerland, but against the wishes of its residents, it formally became part of the EU customs territory on 1 January 2020. VAT will apply, but the tax rate will remain that of Switzerland (much lower than that of Italy). A border crossing will be established.