Abstract: Children with congenital craniosynostosis syndromes have a high incidence of obstructive sleep apnea (OSA). Obstructive sleep apnea has significant consequences including impaired growth, learning and behavioral problems, and cardiovascular morbidity. Adenotonsillectomy is the treatment of choice for OSA in otherwise healthy children. In children with craniosynostosis syndromes, airway abnormalities may exist at multiple levels, but midface hypoplasia leading to a reduced nasopharyngeal airway is a common significant factor; here, even normal-sized adenoids and tonsils may contribute to obstruction. To date, few studies have evaluated adenotonsillectomy for the treatment of OSA in children with syndromic craniosynostosis. In this study, we assessed the effectiveness of adenotonsillectomy by comparing preoperative and postoperative sleep study data. We also evaluated whether adenotonsillectomy could obviate the need for tracheostomy in these patients. Five children with syndromic craniosynostosis and moderate to severe OSA underwent adenotonsillectomy at a mean age of 4.0 years (range, 1.7–5.1 y). Two patients (40%) showed improvement in OSA severity grade and 1 patient had complete resolution. Three children (60%) avoided tracheostomy and had no further airway surgery. Our results provide evidence to support the use of adenotonsillectomy in treating OSA in children with syndromic craniosynostosis. Adenotonsillectomy should be considered before tracheostomy or more major surgery in this patient group.