Fibrous dysplasia (FD) is a skeletal developmental anomaly, which is non-hereditary and idiopathic in origin. It is characterized by the replacement of normal bone with the excess proliferation of fibrous tissue in irregular bony trabeculae. Patients might complain of swelling, pain, or numbness on the affected side. The incidence of monostotic FD (MFD) is four times more than that of polyostotic fibrous dysplasia. In MFD, the maxilla is more commonly affected than the mandible. The clinical behavior and rapid progression of FD renders the treatment challenging. The malignant potential is 0.5% for untreated cases. Here, we present a case of FD involving the mandible. The clinical diagnostic approach, different imaging modalities, and histological examination methods for definitive diagnosis have been elaborated.