Graves' orbitopathy (GO), also named thyroid-associated orbitopathy (TAO) or thyroid-eye disease (TED), is an autoimmune inflammatory disease of the orbit and the most important extrathyroidal manifestation of Graves' disease. After an initial inflammatory ("active") phase of undefined duration, GO progressively burns out within 18-24 months but may cause fibrotic changes and remodeling of the orbital tissues, with abnormal appearance and visual dysfunctional as sequelae. GO has a negative impact on the quality of life of affected individuals because of its disfiguring (exophthalmos) and dysfunctional (diplopia) features, and can only partially be prevented by intervening on to change modifiable risk factors. In the large majority of cases GO is mild, self-limiting and non-progressive, requiring only local measures (artificial tears, ophthalmic gels) and control of risk factors. Very rarely, GO is sight-threatening, due to compressive dysthyroid optic neuropathy (DON) and/or exophthalmos-related corneal breakdown, requiring prompt treatment with very high doses of intravenous glucocorticoids (ivGCs), local treatments, and/or orbital decompression surgery.