The basking shark (Cetorhinus maximum) is an extremely large, non-agressive shark that is second only to the whale shark as the largest living fish. It grows up to 10 meters (33 feet) in length and weighs up to 6,000 kilograms (13,200 pounds). It lives in oceanic surface waters feeding entirely upon plankton filtered by stiff bristles on its long gill arches.

The basking shark belongs to the family Cetorrhinidae.