Italian war crimes have mainly been associated with the Kingdom of Italy, Fascist Italy and the Italian Social Republic starting from the Italo-Turkish War then to Pacification of Libya, the Second Italo-Ethiopian War, the Spanish Civil War, the World War II and the Unified Task Force.

In 1911, Italy went to war with the Ottoman Empire and invaded Ottoman Tripolitania. One of the most notorious incidents during this conflict was the October Tripoli massacre, wherein an estimated 4,000 inhabitants of the Mechiya oasis were killed as retribution for the execution and mutilation of Italian captives taken in an ambush at nearby Sciara Sciat. Over the course of three days, Libyan and Turkish men, women, and children were indiscriminately murdered in the streets, in their houses, farms, and gardens. Libyan and Turkish women were also reportedly raped and sexually assaulted by Italian troops, prompting ferocious and violent retaliation against captured Italian troops by Ottoman soldiers. In another incident during the war reported by a British officer serving with the Turkish forces, Italian soldiers burned several hundred civilians in a mosque, wherein women and children had taken refuge. In 1912, 10,000 Turkish and Arab troops were imprisoned in concentration camps in Libya, and all Turkish troops were executed.

During the Italian occupation of Southwestern Anatolia following the Ottoman defeat and surrender in the First World War, a large number of reports and complaints reportedly emerged of Italian occupation troops committing rape against Turkish civilians in the cities and villages they occupied. On the other hand, some reports also suggest benevolence and fairness, with Italian forces sometimes even handing out chocolate and postcards to Turkish children, as well as providing refuge and shelter to displaced Turkish civilians. Others state that the behavior of the Italian troops in Turkey was mixed, and was generally “arbitrary”, and depended on the particular circumstances.

In 1923, Benito Mussolini embarked upon a pacification of Libya campaign to consolidate control over the Italian territory of Libya and Italian forces began to occupy large areas of Libya in order to allow Italian colonists to rapidly settle in it. They were met with resistance by the Senussi who were led by Omar Mukhtar. Civilians suspected of collaboration with the Senussi were executed. Refugees from the fighting were subject to bombing and strafing by Italian aircraft. In 1930, in northern Cyrenaica, 20,000 Bedouins were relocated and their land was given to Italian settlers. The Bedouins were forced to march across the desert into concentration camps. Starvation and other poor conditions in the camps were rampant and the internees were used for forced labour, ultimately leading to the death of nearly 4,000 internees by the time they were closed in September 1933. Accounts of war crimes and atrocities committed by Rodolfo Graziani’s forces report that they threw prisoners from high altitude planes, ran them over with tanks while they were still alive, raped and disemboweled women, indiscriminately bombarded villages with mustard gas, and did not spare women or children. It is estimated that 20,000 to 100,000 Libyans were killed from the period of 1929-1934 in total, via death marches, chemical gas attacks, and brutal conditions in desert concentration camps. The United Nations estimated that during the entire Italian colonial period, from 1912 to 1942, 250,000-300,000 Libyan civilians lost their lives under Italian colonialism. Ali Abdullatif Ahmida suggests this figure is higher, at 500,000.

During the Second Italo-Ethiopian War, Italian violations of the laws of war were reported and documented. These included the use of chemical weapons such as mustard gas, the use of concentration camps in counter-insurgency, and attacks on Red Cross facilities. Italian authorities claimed that these actions were in response to the Ethiopians' use of Dum-Dum bullets, which had been banned by declaration IV, 3 of the Hague Convention, and mutilation of captured soldiers.

According to the Ethiopian government, 382,800 civilian deaths were directly attributable to the Italian invasion. 17,800 women and children were killed by bombing, 30,000 people were killed in the massacre of February 1937, 35,000 people died in concentration camps, and 300,000 people died of privations due to the destruction of their villages and farms. The Ethiopian government also claimed that the Italians destroyed 2,000 churches and 525,000 houses, while confiscating or slaughtering 6 million cattle, 7 million sheep and goats, and 1.7 million horses, mules, and camels, leading to the latter deaths.

During the 1937–1941 Italian occupation, atrocities also occurred; in the February 1937 Yekatit 12 massacres as many as 30,000 Ethiopians may have been killed and many more imprisoned as a reprisal for the attempted assassination of Viceroy Rodolfo Graziani. A 2017 study estimated that 19,200 were killed - a fifth of the population of Addis Ababa. The Ethiopian Orthodox Tewahedo Church was especially singled out. Thousands of Ethiopians also died in concentration camps such as Danane and Nocra.

75,000 Italian soldiers of the Corpo Truppe Volontarie fought on the side of the Nationalists during the Spanish Civil War, as did 7,000 men of the Aviazione Legionaria. While they also bombed valid military targets such as the railway infrastructure of Xativa, the Italian air force partook in many bombings of civilian targets for the purposes of "weakening the morale of the Reds". One of the more notable bombings was the Bombing of Barcelona, in which 1,300 civilians were killed, with thousands more being wounded or dehoused. Other cities subjected to terror bombing by the Italians included Durango, Alicante, Granollers, and Guernica.