The Pliocene hominid species Australopithecus afarensis is represented by cranial, dental, and mandibular remains from Hadar, Ethiopia, and Laetoli, Tanzania. These fossils provide important information about the cranial anatomy of the earliest known hominids. Because complete crania or skulls are not known, we produced a composite reconstruction of an adult male skull based on 13 specimens from the Hadar Formation. The reconstruction serves as a testable hypothesis regarding functional relationships in the A. afarensis skull and is the basis for the comparative study presented here.