The domestic dog varies remarkably in cranial morphology. In fact, the differences in size and proportion between some dog breeds are as great as those between many genera of wild canids. In this study, I compare patterns of intracranial allometry and morphologic diversity between the domestic dog and wild canid species. The results demonstrate that the domestic dog is morphologically distinct from all other canids except its close relatives, the wolf‐like canids. Following this, I compare patterns of static and ontogenetic scaling. Data on growth of domestic dogs are presented and used to investigate the developmental mechanisms underlying breed evolution. Apparently, most small breeds are paedomorphic with respect to certain morphologic characters. In dogs and other domestic animals, morphologic diversity among adults seems to depend on that expressed during development.