The exact nature of lymphangiomas of the orbit is controversial. Nineteen cases with typical clinical, surgical, and histopathologic findings are presented. These tumors are diffuse, slowly progressive, difficult to remove, and relatively insensitive to irradiation. They frequently hemorrhage, causing rapid increase in proptosis, which may require emergency surgery, and they fluctuate in size with upper respiratory tract infections. Optic disc edema and amblyopia secondary to astigmatism are occasionally noted.