The bluegill (Lepomis macrochirus) is a species of freshwater fish. It is a member of the sunfish family (family Centrarchidae) of order Perciformes. It is native to a wide area of North America, from Québec to northern Mexico, and has been widely transplanted to stock game fish for anglers.

Of typical sunfish body shape, the bluegill’s most notable feature is the blue or black “ear”, actually an extension of the gill cover called the opercular flap. It can be distinguished from similar species by the (not always pronounced) vertical bars along its flanks. The bluegill grows to a maximum overall length of approximately 40 cm (16 in).

Bluegills are popular game fish, caught with both flies and live bait, chiefly at dawn and dusk. They are noted for seeking out underwater vegetation for cover; their natural diet consist largely of small invertebrates and very small fish. Because of their size and the method of cooking them, bluegills are often called panfish.

In some locations where it has been transplanted, it is considered a pest. Trade in the species is prohibited in Germany.