The southern right whale (Eubalaena australis) is a baleen whale, one of three species classified as right whales belonging to the genus Eubalaena.

Like other right whales, the southern right whale is readily distinguished from others by the callosities on its head, a broad back without a dorsal fin, and a long arching mouth that begins above the eye. Its skin is very dark grey or black, occasionally with some white patches on the belly. The right whale's callosities appear white due to large colonies of cyamids (whale lice).

It is almost indistinguishable from the closely related North Atlantic and the North Pacific right whales, displaying only minor skull differences. It may have fewer callosities on its head and more on its lower lips than the two northern species.

Approximately 10,000 southern right whales are spread throughout the southern part of the Southern Hemisphere. The size of an adult female is 15 m (49 ft) and can weigh up to 47 tonnes (46 long tons; 52 short tons), with the larger records of 17.5–18 m (57–59 ft) in length and 80 tonnes (79 long tons; 88 short tons) in weight, making them slightly smaller than other right whales in Northern Hemisphere.

Right whales cannot cross the warm equatorial waters to connect with the other (sub)species and (inter)breed: their thick layers of insulating blubber make it impossible for them to dissipate their internal body heat in tropical waters. However, based on historical records and unconfirmed sightings in modern periods, E. australis actually do occur in equatorial waters. The proportion and numbers of molten-coloured individuals are notable in this species compared with the other species in the Northern Hemisphere. Some whales remain white even after growing up.

Approximately 5cm long.