The Allied effort to secure the Italian island of Sicily followed hard on the heels of the North African Campaign, when an Anglo-American force had finally hemmed the Axis forces into Tunisia where they were obliged to surrender on 13 May 1943, over a quarter of a million troops going into captivity. Now, intending to open the sea lanes across the Mediterranean for the first time since 1940 and knock Italy out of the war, the Allies invaded Sicily on the night of 9-10 July 1943. After just eight weeks of planning and preparation, sea and airborne landings were made on the southern and south-eastern areas of the island. The campaign that followed included a further British airborne landing in mid-July before Axis forces were obliged to withdraw across the Straits of Messina to the Italian mainland, leaving Sicily in Allied hands. The six weeks of fighting cost the Allied forces almost 20,000 men killed, wounded and missing, while their opponents lost around 100,000, with a further 123,000 prisoners, mostly Italian.

The Sicily Campaign was the first occasion that Allied forces successfully took the fight onto the home territory of an Axis power, and it provided the springboard for the Allied return to continental Europe for the first time since Dunkirk via the invasion of the Italian mainland. It marked the beginning of formal Anglo-US co-operation, which was to be vital to the success of the subsequent campaign in North-West Europe.