Myositis ossificans is ossification and bone formation within muscle. It is a rare and unusual pathologic entity that has defied most efforts to establish definite etiology, pathogenesis, and satisfactory treatment. Myositis ossificans is mainly of 2 types: myositis ossificans progressiva (MOP) and myositis ossificans traumatica (MOT). Myositis ossificans idiopathic is also reported in the literature. When it affects the muscles of mastication, it causes severe trismus. Computed tomography scans and magnetic resonance imaging can effectively delineate the calcified mass. In this article, we present a case of MOT of the medial, lateral pterygoid, and contralateral temporalis muscles.