Cottus is a genus of the mainly freshwater ray-finned fishes belonging to the family Cottidae, the typical sculpins.

[1] Cottus was first proposed as a genus by Carl Linnaeus in the 10th edition of the Systema Naturae when he described the European bullhead (Cottus gobio) and in 1850 this species was designated as the type species of the genus by the French ichthyologist Charles Frédéric Girard.

[2] The 5th edition of the Fishes of the World classifies this genus within the subfamily Cottinae of the family Cottidae.

[3] Other authorities have found that the Cottidae, as delimited in the 5th edition of Fishes of the World, is paraphyletic and that the monophyletic grouping is the freshwater sculpins, including the Baikal sculpins, while most of the marine taxa are classified within the family Psychrolutidae.

[5] There are currently around 70 recognized species in this genus:[1][6] Cottus is derived from the Greek kottos, and is a latinisation that word, the original form of it being koviós or kóthos.