Cod fisheries are fisheries for cod. Cod is the common name for fish of the genus Gadus, belonging to the family Gadidae, and this article is confined to the three species that belong to this genus: the Atlantic cod, the Pacific cod and the Greenland cod.

Cod are demersal fish found in huge schools confined to temperate waters in the northern hemisphere. Atlantic cod are found in the colder waters and deeper sea regions throughout the Northern Atlantic. The Pacific cod is found in both eastern and western regions of the Pacific. Atlantic cod can grow to 2 metres (6.6 ft) in length. Its average weight is 5 to 12 kilograms (11 to 26 lb), but specimens weighing up to 100 kilograms (220 lb) have been recorded. Pacific cod are smaller, and may grow up to 48 to 49 centimetres (19 to 19 in) and weigh up to 15 kilograms (33 lb). Cod feed on mollusks, crabs, starfish, worms, squid, and small fish. Some migrate south in winter to spawn. A large female lays up to five million eggs in midocean, a very small number of which survive.