Specimens that give new information on the tooth eruption sequence in European Hyaenodon are described. These specimens show a marked difference from the tooth eruption sequence established for North American Hyaenodon. The eruption of p4 after p3 and m3 and the earlier eruption of the permanent canine in European specimens versus the eruption of p4 before p3 and m3 and the eruption of the permanent canine as the last tooth in North American specimens indicate divergent evolutionary pathways for New and Old World lineages. In conjunction with other skeletal differences, described in the literature, our findings support the need for a reanalysis of the taxonomy of Hyaenodon.