OBJECTIVE: To assess the effectiveness of multiplanar mandibular distraction by evaluating the treatment effect and 1-year stability, measuring changes on the affected and nonaffected sides, and evaluating correction of the occlusal plane and oral commissure cant. PATIENTS AND METHOD: Eleven patients aged 5 to 9.4 years (mean 6.7 years ) who underwent unilateral multiplanar mandibular distraction were included, 10 with hemifacial microsomia and one temporomandibular joint ankylosis. Intermaxillary elastics were applied to intraoral dental devices during and after distraction until bony consolidation and occlusal interdigitation were achieved. Radiographs were taken and measured before distraction, after vertical distraction, after completion of distraction, and 1 year after treatment. Frontal facial photographs were obtained to analyze the changes in the position of the oral commissure. RESULTS: The facial profile was improved by sagittal mandibular advancement. Although the facial height increased 6.6 mm during vertical distraction, with a net gain of 5.8 mm in follow-up, the mandibular plane angle was maintained. The affected mandibular length increased 8.3 mm after distraction and remained unchanged after 1 year. Ramus height increased 12.7 mm after distraction and relapsed 3.8 mm at follow-up (30%). The affected body length demonstrated postoperative growth of 3.1 mm. Correction of the chin deviation was 9.8 mm after distraction and relapsed 1.6 mm (16.3%) after 1 year. Canting of the occlusal plane and oral commissure was corrected and remained stable. CONCLUSION: Multiplanar mandibular distraction is an effective treatment for correcting facial asymmetry in young children. The 1-year follow-up revealed that the new sagittal jaw relation and mandibular body length were stable, and the achieved occlusal interdigitation was well maintained. However, the ramus height and chin deviation demonstrated some relapse.