To examine the application of a modified fixed reverse twin-block appliance (TBA) in adults with an Angle Class III malocclusion and anterior crossbite.Thirty-two adults with an Angle III malocclusion were recruited. An associated temporomandibular disorder (TMD) was found in 18 patients, laterognathism in 21, and both conditions in the remaining 12 patients.A modified fixed reverse TBA was used to posture the mandible back, divert bite force and centre the dentition. The malocclusion, laterognathism and temporomandibular disorders were concurrently treated. The outcome was evaluated radiographically and the findings were analyzed via Electronic Measurement Scale software.Treatment was shown to be effective and could significantly shorten the course of treatment and avoid orthognathic surgery. The average course of treatment was 14 months, during which time, the mandible was postured back and the dentition was successfully aligned and levelled. Most patients achieved an edge-to-edge occlusion of the anterior teeth after 7-10 days of appliance wear. Most symptoms of TMD were relieved after 1 month and the laterognathism resolved in 4-5 months.A modified fixed reverse TBA was an effective non-surgical strategy for the treatment of selected Angle Class III malocclusions with an anterior crossbite in adults.