The purpose of this study was to review an interesting case of recurrent orbital sinus histiocytosis. The patient initially failed surgery, chemotherapy, and steroid therapy, only to have a durable response to low-dose radiation therapy of the orbits, lasting 6 and 11 years, respectively. Because there are few documented responses to radiotherapy, we present a case report in conjunction with the clinical, radiographic, and histopathologic information as well as a literature review of similar cases.