A rare case of a diffuse calvarial meningioma in a sixty-three year-old female is reported. The patient presented with headache, painful proptosis and chemosis of the left eye. Imaging showed that the frontoparietal calvarium on both sides and the left orbital roof were thickened. The thickened bone showed patchy rarefaction. In relationship to the thickened bone, there was an enhancing en-plaque meningioma. The tumour extended on to the superolateral aspect of the left orbit and resulted in proptosis. Excision of the left frontoparietal calvarium and the orbital tumour was performed. The management of diffuse calvarial meningioma is discussed and the relevant literature is briefly reviewed.