Graves' disease, the most common orbital disorder, affects approximately 0.5 % of the population of the United States. It is the underlying cause in 15% to 28% of cases of unilateral exophthalmos and in 80% of cases with bilateral exophthalmos. Also called "thyroid-associated ophthalmopathy", autoimmune thyroid disease," "endocrine exophthalmos," and "thyroid eye disease", Graves' disease presents with enlargement of the extraocular muscles, increased orbital fat volume, and venous stasis caused by increased orbital pressure. This article discusses the clinical evaluation and radiologic findings of this common orbital disorder.