Purpose of Review <p>Epstein-Barr virus (EBV) is the likely cause of multiple sclerosis (MS). However, its role in the pathogenesis of MS remains uncertain. The purpose of the review is to outline the hypotheses of how EBV causes MS and why EBV is a potential target for both MS prevention and treatment.</p> Recent Findings <p>Recent epidemiological findings show that exposure to EBV is necessary but insufficient to develop MS and that exposure to EBV occurs before the onset of the disease. Immunological data supports EBV as a potential trigger of autoimmunity via molecular mimicry or immune dysregulation. Alternatively, poor immunological control of EBV infection may be driving MS disease activity via latent-lytic cycling either within the central nervous system or the periphery.</p> Summary <p>Immunological and virological findings support the testing of anti-EBV agents as potential preventive strategies and treatments for MS.</p>