A 14-year-old boy with 11 mm of proptosis and exposure keratopathy secondary to an orbital lymphangioma underwent surgical debulking with a carbon dioxide laser through a lateral orbitotomy combined with a 3-wall orbital decompression. The proptosis was reduced by approximately 2 mm as a result of the debulking procedure, but a further 5 mm reduction was achieved with the orbital decompression. No serious adverse effects were encountered. Bony orbital decompression may be a useful alternative treatment in patients with severe proptosis secondary to orbital lymphangioma.