The fourhorn sculpin (Myoxocephalus quadricornis or Triglopsis quadricornis) is a species of fish in the Cottidae family. It is a demersal fish distributed mainly in brackish arctic coastal waters in Canada, Greenland, Russia, and Alaska, and also as a relict in the boreal Baltic Sea. There are also freshwater populations in the lakes of Norway, Sweden, Finland and Karelia (NW Russia) and in Arctic Canada (Nunavut and Northwest Territories).