OBJECTIVE To assess speech outcomes following midface advancement and to explore whether the type of advancement surgery affects speech differently in patients with craniofacial dysostosis. METHODS Prospective, before-after group design. METHODS Fifteen consecutive patients were included in the study. Eight underwent advancement by osteotomy and seven by distraction. All patients were seen preoperatively and at least once postoperatively. METHODS Percentage of consonants correct, nature and type of articulation errors, nasalance score, severity ratings of resonance and of velopharyngeal function using nasendoscopy and lateral videofluoroscopy, and amount of forward advancement. RESULTS No statistically significant differences were found between groups for pre- and postoperative changes of percentage of consonants correct (p = .755, median difference 3.0, 95% confidence interval for median difference [-14.22, 20.22]) and nasalance (p = .171, median difference = -12.00, 95% confidence interval for median differences [-30.46, 6.46]). There was no statistically significant correlation between amount of forward advancement and nasalance (r = .87, p = .799) and percentage of consonants correct (r = -.550, p = .064). Findings from lateral videofluoroscopy and nasendoscopy are described. Individual changes of speech outcomes are reported. CONCLUSIONS In view of the small sample size, results need to be interpreted with caution. However, the study adds to current limited knowledge with this clinical group. Further research with bigger sample sizes and randomization of patients into the different surgical groups is warranted.