A 46-year-old male was referred to the Ophthalmology Service for a 7-year history of bilateral proptosis and a presumptive diagnosis of thyroid eye disease. Past medical history was only significant for autoimmune pancreatitis. All laboratory testing including tests of thyroid function were within normal limits. The patient underwent orbital biopsy and was found to have plasma cells containing mainly IgG4 immunoglobulin that was consistent with IgG4-related disease. The patient was treated with oral prednisone and the proptosis resolved within 3 weeks.