Thyroid eye disease (TED) is an inflammatory autoimmune condition now recognized as being associated not only with Graves hyperthyroidism but also with euthyroidism and hypothyroidism. A high index of suspicion is required to diagnose TED and to recognize sight-threatening disease. Care is best provided in a multidisciplinary setting among primary care clinicians, endocrinologists, and ophthalmologists. This review summarizes the pathophysiology, risk factors, clinical presentation, and activity and severity evaluation of TED as well as the most recent advances in its treatment.