Purpose: Developing teeth are used to assess maturity and estimate age in a number of disciplines. The purpose of this investigation was to study the dental maturation in children with Crouzon or Apert syndrome compared with nonsyndromic controls. Patients and Methods: Records of 40 children with Crouzon syndrome (18 boys and 22 girls, aged 4.0 to 17.9 years) and 28 children with Apert syndrome (10 boys and 18 girls, aged 3.9 to 15.1 years) were referred to the Department of Orthodontics, Cleft Palate Team and Craniofacial Team, Erasmus MC-Sophia. Data from syndromic children were compared with data from 451 nonsyndromic children (225 boys and 226 girls, aged 2.9 to 16.9 years). From panoramic radiographs, dental maturation was determined for patients with Crouzon and Apert syndromes and compared with data collected from control children. Logistic functions were constructed for dental maturation over time for syndromes and gender. Results: Statistically significant gender differences in dental maturation scores were found for girls with Crouzon (P < .05) and Apert syndrome (P < .05). Patients with Apert syndrome demonstrated a significantly delayed dental maturation (P < .05), while patients with Crouzon syndrome showed a nonsignificant delay. Conclusions: Dental maturation in patients with Apert syndrome was more delayed than in patients with Crouzon syndrome. The delay of tooth formation in patients with Crouzon or Apert syndrome suggests a possible common genetic association.