Killer whales are the largest of the dolphin family. Adult males reach up to 9.4 m in length although 8.2 m is average. Females typically reach 7 m in length with the maximum about 8.5 m. Maximum weight is about 7 metric tons.
Body form is stocky, the snout is blunt, and the flippers are large and paddle-shaped.
In males the dorsal fin may be up to 1.8 m tall, but is considerably shorter in females. Coloration is black dorsally and white ventrally from the chin to slightly behind the anus. An area of white extends up the side posterior to the dorsal fin and an oval white patch is located just above and behind the eye. Each side of both jaws has 10-12 slightly curved teeth that are about 13 cm in length and interlock when the mouth is closed. The teeth are oval in cross section.