'MC6' was a British unrealised naval undertaking for air and gunfire attacks on coastal targets in the Italian-held Dodecanese islands group by the warships of Admiral Sir Andrew Cunningham’s Mediterranean Fleet (11/12 January 1941).

The warships which sortied from Alexandria as Force 'X' were the battleship Barham, the fleet carrier Eagle, the light cruiser Ajax and a number of destroyers including the Australian Stuart. Force 'X' was recalled after the fleet carrier Illustrious, which was to have provided air cover for part of the more important 'Excess' undertaking, suffered damage and had therefore to be replaced by Eagle.