The siege of Tobruk () took place between 10 April and 27 November 1941, during the Western Desert campaign (1940–1943) of the Second World War. An Allied force, consisting mostly of the 9th Australian Division, commanded by Lieutenant-General Leslie Morshead, was besieged in the North African port of Tobruk by German and Italian forces. The tenacious defenders quickly became known as the Rats of Tobruk. After 231 days, they were finally relieved by the British Eighth Army.
In late 1940, the Allies had defeated the Italian 10th Army during Operation Compass (9 December 1940 – 9 February 1941) and trapped the remnants at Beda Fomm. On 22 January 1941, Tobruk's Italian garrison surrendered.