The 'Crimean Defensive Operation' was the Soviet defence of Crimea (18 October 1941/4 July 1942).

In its entirety, the Crimea campaign lasted eight months as Soviet forces attempted to prevent the seizure of Crimea, and most particularly the strategically important port city of Sevastopol, which was also a naval shipyard and the base of the Black Sea Fleet, by Axis forces. The campaign was one of the bloodiest battles on the Eastern Front during World War II, and began as German and Romanian forces tried and succeeded in forcing a passage through the Perekop isthmus, linking the very north of the peninsula with the rest of the USSR at Perekop, from the autumn of 1941 to the summer of 1942.

From 26 September 1941 Germans troops of Generaloberst Erich von Manstein’s 11^th Army and Romanian troops of General de corp de armatâ Petre Dumitrescu’s 3^rd Army and General de corp de armatâ Iosif Iacobici’s (from 9 November General de divizie Constantin Constantinescu’s) 4^th Army were committed in this campaign against the Soviet troops of General Polkovnik Fyedor I. Kuznetsov’s (from 2 November 1941 General Leytenant Pavel I. Batov’s and from 18 December 1941 General Leytenant Vladimir N. Lvov’s) 51^st Army and elements of Vitse Admiral Filipp S. Oktyabrsky’s Black Sea Fleet. Overall local command was exercised by General Leytenant Dmitri T. Kozlov’s Trans-Caucasus Front (from 30 December 1941 the Caucasus Front). After the campaign, Crimea was occupied by Generalfeldmarschall Wilhelm List’s Heeresgruppe 'A' with Generaloberst Richard Ruoff’s 17^th Army as its major subordinate formation.

Based largely on the formations of General Erik Hansen’s LIV Corps, the Axis offensive swiftly overran all of Crimea with the exception of Sevastopol in the west and Kerch in the east, of which the latter held out for only a short time before its garrison forces were evacuated across the Strait of Kerch to the Taman peninsula and then landed once again in the 'Kerch-Feodosiya Amphibious Operation' on 25 December 1941, and the latter held until its loss on 4 July 1942 to the 'Störfang' offensive on 4 July 1942.