Ocean Park Hong Kong, commonly known as Ocean Park, is a marine mammal park, oceanarium, animal theme park and amusement park situated in Wong Chuk Hang and Nam Long Shan in the Southern District of Hong Kong. It is the second largest theme park in Hong Kong, after Hong Kong Disneyland, as well as the largest theme park in Hong Kong by area. It is also the second oldest theme park in Hong Kong, after the now-defunct Lai Chi Kok Amusement Park which closed on 31 March 1997, four months before the 1997 handover.

A marine mammal park is a commercial theme park or aquarium where marine mammals such as dolphins, beluga whales and sea lions are kept within water tanks and displayed to the public in special shows. A marine mammal park is more elaborate than a dolphinarium, because it also features other marine mammals and offers additional entertainment attractions. It is thus seen as a combination of a public aquarium and an amusement park. Marine mammal parks are different from marine parks, which include natural reserves and marine wildlife sanctuaries such as coral reefs, particularly in Australia.