Autotransplantation is an option for tooth replacement when a suitable tooth is available and anatomic circumstances are favorable. This case report describes successful orthognathic treatment that was combined with autotransplantation of a maxillary third molar. A 20-year-old woman had mandibular protrusion and facial asymmetry. Five years previously, her mandibular right first molar had been extracted because of dental caries. After preoperative orthodontic treatment, we performed a LeFort I procedure and a bilateral intraoral vertical ramus osteotomy to correct the patient's mandibular protrusion and facial asymmetry. During the postoperative orthodontic treatment, the maxillary left third molar was autotransplanted into the mandibular right first molar site. The total treatment period was 24 months. As a result of these therapeutic treatments, the patient's facial appearance was improved, and an implant was unnecessary. The autotransplanted tooth effectively supported the adjacent teeth and maintained her chewing ability.