Paraneoplastic neurologic syndromes arise when an immune response directed against a distant tumor cross-reacts with components of the nervous system, producing a wide range of neuro-ophthalmic manifestations. These disorders can involve either the afferent or efferent visual pathways and often present diagnostic challenges, particularly because visual symptoms may precede the detection of an underlying malignancy by months or years. This chapter focuses on paraneoplastic processes affecting the efferent visual system, which manifest as abnormalities of ocular motility, including opsoclonus-myoclonus, ocular flutter, nystagmus, gaze palsies, and neuromuscular junction disorders such as Lambert-Eaton myasthenic syndrome and myasthenia gravis. Paraneoplastic antibodies – including anti-Hu, anti-Ri, and anti-Yo – frequently guide diagnosis, although negative testing does not exclude disease. Tumors most commonly associated with these syndromes include small-cell lung carcinoma, breast cancer, gynecologic malignancies, thymoma, melanoma, and neuroblastoma in children. Pediatric presentations, particularly opsoclonus-myoclonus syndrome, require special consideration because early tumor detection and intensive immunotherapy are critical to limiting long-term neurologic sequelae. Evaluation typically involves a thorough neurologic examination, neuroimaging, cerebrospinal fluid analysis, antibody testing, and whole-body imaging to search for an occult neoplasm. Management centers on treatment of the underlying cancer together with immunomodulatory therapy, yet therapeutic decisions must balance suppression of autoimmune injury with preservation of antitumor immunity, especially in the era of immune checkpoint inhibitors. Continued advances in antibody discovery and tumor-detection methods are refining the diagnostic approach and guiding more personalized care for patients with paraneoplastic neuro-ophthalmic disease.