Myositis Ossificans is characterized by the heterotopic formation of bone inside a muscle, tendons and ligaments. This pathology is traditionally classified into two groups: Myositis Ossificans Progressiva and Myositis Ossificans Traumatica. The pathogenesis of Myositis Ossificans Traumatica is still not well established. Because it is uncommon in the maxillofacial region, there are no consolidated treatment protocols. The purpose of this study is to present a case of a patient who evolved with Myositis Ossificans Traumatica of the masticatory muscles after performing third molar extraction.