The aetiological spectrum of sphenoid sinus mucocele includes congenital anomaly, trauma, infection, allergy and surgery of the sphenoid sinus. Enlargement of the mucocele, even with a short history, can result in progressive expansion of the sinus and extension of the lesion into the pituitary fossa, the suprasellar region, nasopharynx, orbits, clivus or ethmoid air cells. It is a benign cystic lesion with an excellent prognosis when treated appropriately. Generally, these lesions are managed by an ear, nose and throat surgeon, but when there is extension into the sellar and parasellar (especially suprasellar) regions they are managed by the neurological surgeon. Sphenoid sinus mucocele should be considered in the differential diagnosis when there is suspicion of a cystic lesion in these regions. Three cases of large sphenoid sinus mucocele are presented, with discussion on their neurosurgical management and a review of the literature.