Paranthropus boisei is a species of Paranthropus geographically isolated to East Africa: Peninj, Olduvai, Omo, East Turkana, and Chesowanja.

Fossil remains indicate P. boisei had a robust masticatory apparatus, a high degree of sexual dimorphism, and a relatively small brain size. As with other paranthropines, P. boisei had very large cheek teeth, a relatively flatter face, a pronounced sagittal crest and a very large mandible. Paranthropine post-crania is very similar to Australopithecus.

The first P. boisei specimen ever discovered consists of a molar, dating to 1.4 - 1.45 Ma. Found in 1955, the molar, known as OH 3, was not taxonomically identified as P. boisei until much later.

The type specimen for P. boisei is OH 5 that was found at Olduvai Gorge and dates to approximately 1.8 million years ago.