The lingcod or ling cod (Ophiodon elongatus), also known as the buffalo cod or cultus cod, is a fish of the greenling family Hexagrammidae. It is the only extant member of the genus Ophiodon. A slightly larger, extinct species, Ophiodon ozymandias, is known from fossils from the Late Miocene of Southern California.

Ophiodon elongatus is native to the North American west coast from Shumagin Islands in the Gulf of Alaska to Baja California, Mexico. It has been observed up to a size of 152 centimetres (60 in) and a weight of 59 kilograms (130 lb). It is spotted in various shades of gray. The lingcod is a popular eating fish, and is thus prized by anglers. Though not closely related to either ling or cod, the name "lingcod" originated because it somewhat resembles those fish. Around 20% of lingcods have blue-green to turquoise flesh.^p. 298 The colour is destroyed by cooking. The colour may be due to biliverdin, but this has not been established beyond doubt.