Italy, officially the Italian Republic, is a country in Southern and Western Europe. It consists of a peninsula that extends into the Mediterranean Sea, with the Alps on its northern land border, as well as nearly 800 islands, notably Sicily and Sardinia. Italy shares land borders with France to the west; Switzerland and Austria to the north; Slovenia to the east; and the two enclaves of Vatican City and San Marino. It is the tenth-largest country in Europe by area, covering 301,340 km² (116,350 sq mi), and the third-most populous member state of the European Union, with nearly 59 million inhabitants. Italy's capital and largest city is Rome; other major cities include Milan, Naples, Turin, Palermo, Bologna, Florence, Genoa, and Venice.

The history of Italy goes back to numerous Italic peoples – notably including the ancient Romans, who conquered the Mediterranean world during the Roman Republic and ruled it for centuries during the Roman Empire. With the spread of Christianity, Rome became the seat of the Catholic Church and the Papacy. Barbarian invasions and other factors led to the decline and fall of the Western Roman Empire between late antiquity and the Early Middle Ages. By the 11th century, Italian city-states and maritime republics expanded, bringing renewed prosperity through commerce and laying the groundwork for modern capitalism. The Italian Renaissance flourished during the 15th and 16th centuries and spread to the rest of Europe. Italian explorers discovered new routes to the Far East and the New World, contributing significantly to the Age of Discovery.

After centuries of political and territorial divisions, Italy was almost entirely unified in 1861, following wars of independence and the Expedition of the Thousand, establishing the Kingdom of Italy. From the late 19th to the early 20th century, Italy industrialised and acquired a colonial empire, while the south remained largely impoverished, fuelling a large immigrant diaspora to the Americas. From 1915 to 1918, Italy took part in World War I with the Entente against the Central Powers. In 1922, the Italian fascist dictatorship was established. During World War II, Italy was first part of the Axis until an armistice with the Allied powers (1940–1943), then a co-belligerent of the Allies during the Italian resistance and the liberation of Italy (1943–1945). Following the war, the monarchy was replaced by a republic and the country made a strong recovery.

A developed country with an advanced economy, Italy has the eighth-largest nominal GDP in the world, the second-largest manufacturing sector in Europe, and plays a significant role in regional and – to a lesser extent – global economic, military, cultural, and political affairs. It is a founding and leading member of the European Union, and is part of numerous other international organizations and forums. As a cultural superpower, Italy has long been a renowned global centre of art, music, literature, cuisine, fashion, science and technology, and the source of multiple inventions and discoveries. It has the highest number of World Heritage Sites (61) and is the fifth-most visited country in the world.

Hypotheses for the etymology of Italia are numerous. One theory suggests it originated from an Ancient Greek term for the land of the Italói, a tribe that resided in the region now known as Calabria. Originally thought to be named Vituli, some scholars suggest their totemic animal to be the calf (Latin: vitulus; Umbrian: vitlo; Oscan: Víteliú). Several ancient authors said it was named after a local ruler Italus.

The ancient Greek term for Italy initially referred only to the south of the Bruttium peninsula and parts of Catanzaro and Vibo Valentia. The larger concept of Oenotria and "Italy" became synonymous, and the name applied to most of Lucania as well. Before the Roman Republic's expansion, the name was used by Greeks for the land between the strait of Messina and the line connecting the gulfs of Salerno and Taranto, corresponding to Calabria. The Greeks came to apply "Italia" to a larger region. In addition to the "Greek Italy" in the south, historians have suggested the existence of an "Etruscan Italy", which consisted of areas of central Italy.

The borders of Roman Italy, Italia, are better established. Cato's Origines describes Italy as the entire peninsula south of the Alps. In 264 BC, Roman Italy extended from the Arno and Rubicon rivers of the centre-north to the entire south. The northern area, Cisalpine Gaul, considered geographically part of Italy, was occupied by Rome in the 220s BC, but remained politically separated. It was legally merged into the administrative unit of Italy in 42 BC. Sardinia, Corsica, Sicily, and Malta were added to Italy by Diocletian in 292 AD, which made late-ancient Italy coterminous with the modern Italian geographical region.

The Latin Italicus was used to describe "a man of Italy" as opposed to a provincial, or one from the Roman province. The adjective italianus, from which Italian was derived, is from medieval Latin and was used alternatively with Italicus during the early modern period. After the fall of the Western Roman Empire, the Ostrogothic Kingdom of Italy was created. After the Lombard invasions, Italia was retained as the name for their kingdom, and its successor kingdom within the Holy Roman Empire.