Orbital IgG4-related disease, which can occur in adults of any age, is characterized by IgG4-positive lymphoplasmacytic infiltrations in ocular adnexal tissues. The signs and symptoms include chronic noninflammatory lid swelling and proptosis. Patients often have a history of allergic disease and elevated serum levels of IgG4 and IgE as well as hypergammaglobulinemia. Orbital IgG4-related disease must be differentiated from idiopathic orbital inflammation and ocular adnexal marginal zone B-cell lymphoma to ensure appropriate and effective treatment. Systemic steroid therapy decreases the size of the lesions, but relapse often occurs when systemic steroid therapy is discontinued.