Military history of Italy during World War II

Italy entered World War II on 10 June 1940 by invading France, joining the German offensive already in progress. Italian dictator Benito Mussolini did so opportunistically as the Allied powers (chiefly France and the United Kingdom) seemed on the verge of collapse. Mussolini's war aim was to expand Italy's national borders, colonial empire and establish client states at the expense of the French, British, Greeks, Yugoslavs and others. While France surrendered on 22 June 1940, the United Kingdom and its Commonwealth continued to fight far beyond the point which Mussolini had thought possible.

Mussolini took Italy to war when its military was unprepared for a major conflict, so the country's armed forces were sent into battle with insufficient resources, many untrained personnel and poor quality equipment (much of it obsolescent). Italy consequently suffered early setbacks, such as in North Africa and Greece, that coloured its relationship with Nazi Germany, and buoyed the confidence of the Allies. Due to Mussolini's ambitious war agenda, Italy's over-stretched resources were spread over several fronts, dissipating its military strength.

In early 1941, it required German intervention to help Italy reverse setbacks and resume the offensive in the Balkans and North Africa. Greece and Yugoslavia were successfully conquered, but partisan uprisings against the occupation forces quickly followed. North Africa was a fast moving campaign, where wide flanking movements and swift redeployments were common. Yet, some Italian infantry divisions were unmotorised, so at a disadvantage to the fully motorised British Commonwealth infantry. Axis forces failed to neutralise the air and naval bases on Malta, which the British used to attack Italian supply convoys bound for North Africa.

Between autumn 1942 and spring 1943, the Axis powers suffered a series of heavy battlefield defeats in North Africa and the Soviet Union (where Italy had committed a force to the German-dominated invasion). The Allied invasion of Sicily in July 1943 brought the fighting onto Italian soil, leading to Mussolini being deposed. In September 1943, Italy agreed the armistice of Cassibile with the Allies, effectively quitting the Axis, just as British and American armies invaded the Italian mainland.

Germany was ready for Italy's defection and occupied central and northern Italy. After freeing Mussolini from captivity, the Germans set him up as the leader of a new puppet state in the north, the Italian Social Republic. This provoked Italian resistance against the German occupation and also a civil war between pro- and anti-fascist Italians in central and northern Italy. In the Allied-held south, the Kingdom of Italy, which faced no resistance movement, officially became a co-belligerent of the Allies and declared war on Germany on 13 October 1943.

The Allied Italian campaign progressed slowly, in part because Allied strategic planning gave the invasion of France greater priority for resources. Also, the mountainous terrain in Italy aided the defenders. Allied victory in Italy came with the 1945 spring offensive prompting the Axis surrender at Caserta on 29 April 1945, which came into effect on 2 May.