Epinephelus marginatus, the dusky grouper, yellowbelly rock cod or yellowbelly grouper, is a species of marine ray-finned fish, a grouper from the subfamily Epinephelinae which is part of the family Serranidae, which also includes the anthias and sea basses. This species is the best known grouper species of the Mediterranean Sea and North Africa coast.

Groupers are fish of any of a number of genera in the subfamily Epinephelinae of the family Serranidae, in the order Perciformes.