We present two paediatric cases of fibrous dysplasia (FD) who presented to the craniofacial neurosurgical clinic with ophthalmological symptoms associated with sinus mucoceles. The first patient presented with a history of orbital cellulitis and an increasing bony swelling around the orbit associated with proptosis. Radiological imaging revealed monostotic FD associated with an obstructive mucocele in the frontal sinus with extension into the orbit. The second patient presented with recurrent conjunctivitis, painful proptosis, rhinitis and a bony peri-orbital swelling. Both patients had histological diagnoses of frontal mucoceles invading the orbit in association with FD. They both underwent frontal craniotomies and excision of the mucocele/fibrous dysplastic complex. In summary, mucocele development is an unusual complication of FD, likely to occur secondary to occlusion of the sinus drainage system. Orbital involvement may lead to visual disturbance caused by pressure effects. A multi-disciplinary approach including maxillofacial surgeons, plastic surgeons and neurosurgeons is advocated.