Osteochondroma is rarely found in oral and maxillofacial regions. The majority of reported osteochondromas occurred in mandibular areas; their occurrence in bones developed by intramembranous ossification is extremely rare. In this report, a case of osteochondroma arising from the pterygoid process of the sphenoid is described. Radiological investigations showed a large bony mass under the left great wing of the sphenoid and involving the left parapharyngeal space. The tumour was compressive to the mandibular ramus and pharyngeal cavity, causing marked disturbance of mouth opening and secretory otitis media. Histopathological examination confirmed the lesion to be osteochondroma.