Exophthalmus is the leading sign of space-occupying lesions of the orbit. Patients may further present with lid swelling, impaired ocular motility and optic neuropathy including a relative afferent pupillary defect, compressive optic disc edema or optic atrophy. Orbital tumors can be classified into various categories depending on the etiology, as lymphoproliferative lesions (in particular non-Hodgkin's lymphoma as the most common malignant orbital tumor of adulthood), optic nerve and meningeal lesions, lacrimal gland lesions, secondary orbital tumors which extend to the orbit from neighboring structures and metastases. Slightly less common are vasculogenic and cystic lesions including cavernous hemangioma as the most common benign orbital tumor of adulthood and dermoid cysts as the most common benign orbital tumor of childhood. Rhabdomyosarcoma is the most common malignant orbital tumor of childhood but has a low total incidence. Orbital tumors might not only cause symptoms like pain, diplopia and loss of visual acuity but may also lead to esthetically disfiguring changes. Particular attention should be paid to underlying systemic diseases and generalized tumor diseases. This article illustrates the approach to a detailed clinical and neuroradiological assessment which is mandatory for the care of orbital tumor patients.