A six-year-old, male, castrated domestic shorthair cat was presented for evaluation of an oralmass. Full physical examination revealed a large hard mass arising from the lateral aspect ofthe caudal part of the left mandible. Abdominal ultrasound and thoracic computed tomography(CT) were performed to rule out metastatic disease. In addition, CT of the skull with intravenouscontrast agent was performed. Histopathological examination of extra-oral biopsies confirmedthe tentative diagnosis of peripheral osteoma. A three-dimensional printed skull was used inconjunction with the CT images to determine the detailed location and extent of the mass andto identify anatomical spatial relationships with important neurovascular structures. Surgicaldebulking of the osteoma was performed. The cat recovered uneventfully but the mass regrewnine months after debulking therapy, sooner than expected. Nevertheless, CT scan of the skullwas suggestive for regrowth of the peripheral osteoma rather than for malignant transformation.The owners did not elect to pursue caudal mandibulectomy.