Malignant orbital tumors represent a broad spectrum of tumors which include primary tumors, secondary tumors (extension from adjacent structures), and metastatic tumors. In addition, orbital inflammation and infection may clinically simulate an orbital neoplasm. In a recent survey of 1264 consecutive patients with suspected orbital tumor referred to an ophthalmic oncology center, 36% were malignant tumors. The percentage of malignant tumors increases with age, due to higher incidence of lymphoma and metastasis in the older age groups. Rhabdomyosarcoma is the most frequent primary malignant orbital tumor in children, and lymphoproliferative disorders including lymphoma are most frequent in older adults. Malignant orbital tumors may also arise from the lacrimal gland and lacrimal sac. Malignant tumors of vascular, neural, fibrous, and osseous origin are rare in the orbit.