Marginal keratitis is an uncommon form of herpetic keratitis, often caused by herpes simplex virus (HSV) and varicella-zoster virus (VZV). It is characterized by a peripheral corneal infiltrate along the limbus, associated with epithelial changes. The pathogenesis involves an immune-mediated response to viral antigens in the corneal tissue, leading to an inflammatory cascade. Diagnosis is largely clinical, based on slit-lamp examination findings. This chapter provides an overview of the epidemiology, pathophysiology, risk factors, clinical features, differential diagnosis, and management strategies for viral marginal keratitis.