For 11 years, 50-year-old woman with euthyroid Graves' disease experienced intermittent exacerbations of her orbitopathy associated with a decline in visual acuity. On each occasion, treatment with systemic corticosteroids led to prompt recovery of vision. Upon referral for consideration for orbital decompressive surgery, computed tomography and magnetic resonance imaging scanning detected bilateral optic-nerve sheath meningiomas, as well as typical findings of Graves' disease. Orbital radiation therapy led to stabilization of visual function and orbital findings, eliminating the need for systemic steroids. To our knowledge, this is the first reported case of Graves' disease associated with bilateral optic nerve sheath meningiomas.