Gardner’s syndrome (GS) is a combination of polyposis, osteomas, fibromas, and sebaceous cysts. The aim of the study is to highlight whether maxillofacial osteoma could represent an early detection symptom of GS. Patients with suspected osteoma of the jaw underwent genetic and radiographical examinations. The database gathered 19 patients with oral osteoma that was histologically diagnosed; the whole sample was positive for APC gene mutation. Other cranial and peripheral locations were reported. Osteoma of the jaw is a crucial predictive factor of GS, and dentists and oral and maxillofacial surgeons must be aware of the importance of a timely diagnosis.