The Italian colonial empire (Italian: Impero coloniale italiano), sometimes known as the Italian Empire (Impero italiano), was a colonial empire that existed between 1882 and 1960. It comprised the colonies, protectorates, concessions and dependencies of the Kingdom of Italy in the 19th and 20th centuries. At its peak, between 1936 and 1941, the colonial empire in Africa included the territories of present-day Libya, Eritrea, Somalia and Ethiopia (the last three being officially named "Africa Orientale Italiana", AOI); outside Africa, Italy possessed the Dodecanese Islands (following the Italo-Turkish War), Albania (initially a protectorate, then in personal union from 1939 to 1943) and also had some concessions in China.

The Fascist government that came to power under the leadership of the dictator Benito Mussolini after 1922 sought to increase the size of the Italian empire and it also sought to satisfy the claims of Italian irredentists. Systematic "demographic colonization" was encouraged by the government, and by 1939, Italian settlers numbered 120,000–150,000 in Italian Libya and 165,000 in Italian East Africa.

During World War II, Italy allied itself with Nazi Germany in 1940 and it also occupied British Somaliland, western Egypt, much of Yugoslavia, Tunisia, parts of south-eastern France and most of Greece; however, it then lost those conquests and its African colonies to the invading Allied forces by 1943. In 1947, Italy officially relinquished claims on its former colonies. In 1950, former Italian Somaliland, then under British administration, was turned into the Italian Territory of Somaliland until it became independent in 1960.

Imperialism in Italy dates back to ancient Rome, and the Latin notion of mare nostrum ("Our Sea", referring to the Mediterranean) has historically been the basis for Italian imperialism, especially during the fascist era. During the Middle Ages and the modern period, the Republic of Venice and the Republic of Genoa controlled networks of "colonies" in the Mediterranean region known as the Venetian Empire and the Genoese Empire respectively. Between the 15th and 16th centuries, Italian explorers contributed to the colonial enterprises of other European countries in the Americas: Cristopher Columbus from Genoa served Spain, Amerigo Vespucci from Florence served Portugal, the Cabot brothers from Venice served England, and Giovanni da Verrazzano from Florence served France.

However, no Italian power took an active role in the scramble for the Americas, with the notable exception of the Pope who acted as an arbiter between European colonial powers during the Renaissance. The geographical position of Italy, located in the center of an internal sea, without an open free access to the ocean, contributed to this purely Mediterranean policy. There was, nonetheless, some interest in the Americas and colonial trade. The Spanish crown often contracted out the slave trade to the Genoese, who were especially active in the port of Panama. Ferdinand I, Grand Duke of Tuscany, made the only Italian attempt to create a colony in the Americas, in what is now French Guiana, organizing in 1608 an expedition to explore the north of Brazil and the Amazon river in 1608 under the command of the English captain Robert Thornton. However, Thornton, on his return from the preparatory expedition in 1609, found Ferdinand I dead and his successor, Cosimo II, was not interested in the project. In 1651, Giovanni Paolo Lascaris, Italian nobleman and Grand Master of the Knights Hospitaller of Malta (at the time a vassal state of the Kingdom of Sicily), possessed four Caribbean islands: Saint Christopher, Saint Martin, Saint Barthélemy, and Saint Croix, which were colonized from 1651 until 1665. No other colonial attempt in the ocean was made and, by 1797, the Venetian and Genoese possessions in the Mediterranean were lost.

Once unified as a nation-state in the late 19th century, Italy intended to compete with the other European powers for the new age of European colonial expansion. It saw its interests in the Mediterranean and in the Horn of Africa, a region yet to be colonized and with access to the ocean. Italy had arrived late to the colonial race and its status as the least of the Great Powers, a position of relative weakness in international affairs, meant that it was dependent on the acquiescence of Britain, France and Germany towards its empire-building.

Italy had long considered the Ottoman province of Tunisia, where a large community of Tunisian Italians lived, within its economic sphere of influence. It did not consider annexing it until 1879, when it became apparent that Britain and Germany were encouraging France to add it to its colonial holdings in North Africa. A last-minute offer by Italy to share Tunisia between the two countries was refused, and France, confident in German support, ordered its troops in from French Algeria, imposing a protectorate over Tunisia in May 1881 under the Treaty of Bardo. The shock of the "Slap of Tunis", as it was referred to in the Italian press, and the sense of Italy's isolation in Europe, led it into signing the Triple Alliance in 1882 with Germany and Austria-Hungary.

While attempts were made to buy the Nicobar Islands from Denmark in 1864 and 1865, the genesis of the Italian colonial empire was the purchase in 1869 of Assab Bay on the Red Sea by an Italian navigation company which intended to establish a coaling station at the time the Suez Canal was being opened to navigation. This was taken over by the Italian government in 1882, becoming modern Italy's first overseas territory.