Walking impairment is a common consequence of multiple sclerosis (MS) that can result in substantial limitations of daily activities and compromised quality of life. Walking impairment is often monitored as an indicator of disease and neurologic disability progression. The worsening of walking performance while undertaking a cognitive task underscores the role of nonmotor impairments in ambulation limitations. Walking impairment has ubiquitous and life-altering consequences, underscoring the importance of continued efforts to identify approaches to prevent and forestall this event, and to restore walking ability in persons with MS.