This review describes the evolutionary history of the mammalian skull vault as a basis for understanding its complex structure. Current information on the developmental tissue origins of the skull vault bones (mesoderm and neural crest) is assessed for mammals and other tetrapods. This information is discussed in the context of evolutionary changes in the proportions of the skull vault bones at the sarcopterygian-tetrapod transition. The dual tissue origin of the skull vault is considered in relation to the molecular mechanisms underlying osteogenic cell proliferation and differentiation in the sutural growth centres and in the proportionate contributions of different sutures to skull growth.