Fibrous dysplasia (FD) of the paranasal sinuses is rare and often presents a diagnostic challenge. It is usually secondary to extension of disease from adjacent bones and is rarely limited to the sinuses. We have described three cases of FD involving the paranasal sinuses, including the first reported case of FD isolated to the sphenoid sinus. A brief update of the clinical aspects, radiographic appearance, diagnosis, and management of craniofacial FD is provided.