Graves' ophthalmopathy is thought to be an autoimmune disease. Whether this disease is organ specific or one of the manifestations of the closely linked Graves' thyroid disease is still a matter of speculation. Many papers describe autoimmunity to orbital antigens, in particular to extraocular muscles, in patients with Graves' ophthalmopathy. In this paper we have tried to give an overview of the evidence for circulating antibodies against extraocular muscle antigens and to discuss their significance in relation to the immunopathogenesis of the disease.