Fibrous Dysplasia (FD) is a developmental disorder of bone that can affect one bone (monostotic type) or multiple bones (polyostotic type). The disease can be associated with hyperpigmentation and endocrinological disorders. It is usually observed in adolescents and young adults and comprises 7% of benign bone tumors. It has a predilection for long bones as well as the craniofacial skeleton. The etiology of FD is not clear but genetic predisposition is suspected. The diagnosis is based on radiological and histopathological examination. There are different treatment approaches including monitoring, medical treatment or surgery. In this article, we present a case of monostotic mandibular fibrous dysplasia of the mandible with clinical, radiographic and histopathological features.