The ocean sunfish or common mola (Mola mola) is the heaviest known bony fish in the world. Adults typically weigh between 247 and 1,000 kg (545–2,205 lb). The species is native to tropical and temperate waters around the globe. It resembles a fish head with a tail, and its main body is flattened laterally. Sunfish can be as tall as they are long when their dorsal and ventral fins are extended.

Sunfish are considered a delicacy in some parts of the world, including Japan, Korea, and Taiwan. Sunfish are frequently caught in gillnets.

A member of the order Tetraodontiformes, which also includes pufferfish, porcupinefish, and filefish, the sunfish shares many traits common to members of this order. The ocean sunfish, Mola mola, is the type species of the genus.