We report on an 81-year-old female who presented with acute, atraumatic right foot drop four weeks after developing herpes zoster in the ipsilateral L4 and L5 dermatomes treated with valacyclovir. Lumbar MRI revealed no explanatory abnormality, and the etiology of her right foot drop was presumed to be due to an outbreak of herpes zoster. After three months of physical therapy and bracing, her right lower extremity weakness greatly improved. We present a comprehensive literature review of atraumatic foot drop pathooetiology, with a focus on herpes zoster as a potential causative agent.