Surgical site infections (SSI) occur in 1.4% to 33.4% of cases after orthognathic surgery. This type of complication is a major concern to surgical teams, but there is no consensus for the prevention and treatment of SSI in orthognathic surgery. The purpose of this descriptive study was to evaluate the severity and the consequences of postoperative infections. The charts of all the patients operated on by the orthognathic surgery team between January 2015 and July 2017 were collected. All types of orthognathic procedures (Le Fort I maxillary osteotomy, bilateral sagittal split mandibular osteotomy, and genioplasty) were screened, and patients diagnosed with SSI were included. Demographic data, timing and severity of the infection, as well as long-term complications were recorded. Five hundred and twelve patients were screened. Forty-one patients (8%) presenting with SSI were included. There were 18 men and 23 women. The site of the infection was mandibular for 38 patients (92.7%) and maxillary for 3 patients (7.3%). The average time between surgery and infection was 31.5 days. Twenty-four patients received isolated oral antibiotics for inflammatory cellulitic reaction (58.8%), 15 patients had a localized collection treated by incision and drainage under local anesthesia (36.6%), and 2 patients had an extensive collection requiring surgical drainage under general anesthesia (4.9%). Five patients (12.2%) needed hardware removal for plate loosening, and 2 patients (4.9%) developed chronic osteomyelitis. Infection following orthognathic surgery is easily treated most of the time with no long-term complications. In cases of patients with potential risk factors for severe infection, antibiotics may be given with curative intents.