A 62-year-old female presented with giant cell granulomatous hypophysitis manifesting as subacute unilateral ophthalmoplegia. Neuroimaging revealed a mass lesion expanding in the pituitary fossa. The mass was totally removed through the transsphenoidal approach. The histological diagnosis was giant cell granuloma. The oculomotor nerve paresis resolved completely 10 days after the operation. Giant cell granulomatous hypophysitis is symptomatically and radiologically indistinguishable from non-functioning pituitary adenoma, but is less likely to cause visual disturbance than pituitary adenoma. Giant cell granulomatous hypophysitis should be considered in the differential diagnosis of sellar and suprasellar lesions, particularly if oculomotor nerve paresis is observed without impaired visual field or acuity.