The common snook (Centropomus undecimalis) is a species of marine fish in the family Centropomidae of the order Perciformes. This species is native to the coastal waters of the western Atlantic Ocean and Caribbean Sea, from southern Florida and Texas to Rio de Janeiro in Brazil.

One of the largest snooks, C. undecimalis grows to a maximum overall length of 140 centimetres (4.6 ft) and a maximum recorded weight of 24 kilograms (53 lb; 3.8 st). Of typical centropomid form, it possesses unremarkable coloration except for a distinctive black lateral line. It can also possess bright yellow pelvic and caudal fins, especially during spawn.

Occurring in shallow coastal waters (up to 20 metres (66 ft) depth), estuaries, and lagoons, the fish often enters fresh water. It is carnivorous, with a diet dominated by smaller fishes, and crustaceans such as shrimps, and occasionally crabs.