Open reduction and internal fixation is the gold standard for managing mandibular fractures with the primary goal of restoring premorbid occlusion status. Malocclusion is one of the most common and functionally significant postoperative complications of mandibular fracture. This study aims to determine the factors that influence the occurrence of malocclusion in patients with mandibular fractures three months after open reduction and internal fixation surgery at Prof. Dr. I GNG Ngoerah Hospital Denpasar. This study was an analytic observational study with a retrospective cohort design. The result is the age️of 40 years, mandibular fracture sites in more than one region, a complex type of mandibular fracture, involvement of other facial bones fracture, waiting time for surgery > 7 days, and internal fixation with wire are risk factors for malocclusion within three months postoperatively. Gender was not statistically associated with the incidence of malocclusion post-operation (p-value 0.705). The combination of internal fixation with maxillo-mandibular fixation (MMF) was a preventive factor for postoperative malocclusion (RR 0.4 (CI: 0.23-0.99)). The results of the multivariate analysis showed that the number of fracture locations in more than one region had the highest effect on the occurrence of postoperative malocclusion by 131.7 times.