Abstract Objective: To study the incidence and related risk factors for new-onset temporomandibular joint disorder after mandibular surgery to provide clinical guidance. Materials and methods: The medical records of patients who underwent open reduction and internal fixation formandibular fractures between September 2020 andJune 2023 were retrospectively analysed, and their personal information and the incidence and pathogenic factors of temporomandibular joint disorder before surgery were recorded. Patients were followed up at 3 months, 6 months, and 1 year after surgery to investigate the incidence and pathogenic factors of postoperative temporomandibular joint disorder. Results: A total of 121 patients were included in this study, 33 of whomdeveloped temporomandibular joint disorder, accounting for 27.27% of the study population, and 88 patients who did not develop temporomandibular joint disorder, accounting for 72.73% of the study population. Univariate analysis revealed significant differences in abnormal occlusion and healing rates, unilateral chewing rates, and deep overbite of the anterior teeth rates (P <0.05). There was no significantdifference in age, sex, fracture area, cause of trauma, infection rate, bruxism rate, empty chewing rate, or postoperative anxiety rate between the two groups (P >0.05). Binary logisticregression analysis revealed that abnormal occlusion and healing (OR=0.044) and unilateral chewing (OR=0.142) may be risk factors for new-onset temporomandibular joint disorder after maxillofacial fracture surgery. Conclusion: During the follow-up period, long-term postoperative occlusal habits should be established, and attention should be given the patients’ postoperative psychological state. Accurate digital reconstruction of the occlusal relationship is needed fortreating mandibular fractures.