Orthognathic surgery describes the surgical movement of the mandible and maxilla to correct dentofacial deformities that result from congenital or traumatic etiologies. Patients with dentofacial deformity often have malocclusion and functional problems related to breathing, chewing, or speech articulation. Furthermore, facial asymmetries or disproportions resulting from dentofacial deformities can adversely affect the psychosocial health of the patient. The goal of orthognathic surgery is to improve both function and form beyond what can be achieved with orthodontic or medical treatments. Some of the most commonly performed orthognathic surgery procedures include Le Fort I osteotomy of the maxilla, bilateral sagittal split osteotomy of the mandible, and genioplasty. Successful outcome after orthognathic surgery should be judged by achieving an improved dental occlusion, enhanced facial aesthetics, and open upper airway. A number of studies have shown that orthognathic surgery leads to significant improvements in the quality of life of patients with dentofacial deformities. Orthognathic surgery also has a significant impact on the upper airway. In patients with severe obstructive sleep apnea, maxillomandibular advancement has the potential to lead to dramatic improvements in the apnea-hypopnea index and lowest oxygen saturation value. With careful surgical planning and execution, consistent outcomes can be expected. This review contains 17 figures, 4 tables, and 32 references. Key Words: aesthetic surgery, dentofacial deformity, genioplasty, Le Fort I, malocclusion, orthognathic surgery, sagittal split osteotomy of the mandible, sleep apnea, virtual surgical planning