Sagittal split ramus osteotomy (SSRO) has wide-ranging indications and results in simultaneous improvements in occlusion and facial appearance. Thus, it is the most frequently used osteotomy for jaw deformities. Its main intraoperative and postoperative complications are massive bleeding, atypical fractures, inferior alveolar nerve paralysis, and relapse. This report describes a case of temporomandibular joint dislocation, a rare complication of SSRO. The patient was a 23-year-old man with mandibular prognathism which was treated by bilateral SSRO. Postoperative x-ray showed that the left temporomandibular joint was dislocated anteriorly. Thus, the patient underwent reoperation, including reduction and re-fixation. Subsequently, it was discovered that the patient had a previous history of recurrent dislocation of the temporomandibular joint. This case illustrates the need for practitioners to be mindful of temporomandibular joint dislocation as a rare complication of SSRO.