'Sleuth' was a British naval undertaking to locate and destroy suspected German blockade runners, on passage from Japan to Germany, in the area to the south-west of the Cocos islands of the Indian Ocean (February/March 1944).

This undertaking involved the fleet carrier Illustrious, New Zealand light cruiser Gambia (replaced on 28 February by the British heavy cruiser Sussex), and destroyers Rotherham and Free Dutch Tjerk Hiddes.