Purpose <p>This report aims to present a case of temporomandibular joint (TMJ) ankylosis in a patient with Neurofibromatosis type 1 (NF1). It is a rare but significant long-term complication of NF1-associated craniofacial dysplasia, potentially aggravated by prior orthognathic surgery.</p> Case presentation <p>The patient, a 58-year-old woman with NF1 developed complete left TMJ ankylosis 14 years after bimaxillary surgery. The patient had a neurofibroma involving the mandibular branch (V3) of the trigeminal nerve, with fatty atrophy of the ipsilateral masticatory muscles. Clinical examination revealed marked facial asymmetry, severe trismus with a maximal mouth opening of 10&#xa0;mm and tilting of the occlusal plane. Imaging studies confirmed ankylosis and extensive craniofacial bone dysplasia. Management was conducted in two surgical stages. The first involved resection of the ankylotic mass and placement of a temporary spacer. The second included orthognathic surgery and insertion of a custom-made TMJ prosthesis. Postoperative assessment showed improved mouth opening to 32&#xa0;mm, with satisfactory aesthetic and functional outcomes.</p> Conclusion <p>NF1 is a genetic disorder characterized by a wide spectrum of systemic manifestations, including craniofacial skeletal anomalies. Although mandibular deformities are commonly observed in patients with facial plexiform neurofibromas, TMJ ankylosis is a rare and poorly documented complication. It underscores the need for individualized surgical planning and long-term surveillance in NF1 patients with facial neurofibromas and skeletal deformities. Clinicians should maintain a high index of suspicion for progressive joint pathology in NF1 patients. Early recognition and proactive management are essential to prevent irreversible joint damage. To our knowledge, this represents the first documented case of true TMJ ankylosis associated with NF1, confirmed both radiologically and surgically.</p> <p><b>Clinical trial number</b>: Not applicable.</p>