Multiple sclerosis (MS) is a chronic, inflammatory, demyelinating, disimmune disease of the central nervous system whose etiology and pathogenesis remain poorly understood, due to its complex and multifactorial nature. Evidence of a bidirectional connection linking the gut microbiome with the intestinal barrier and the immune system (the gut-brain axis) may have implications for the pathogenesis of inflammatory demyelinating diseases such as MS. This narrative review summarizes the evidence for the gut-brain axis involvement in the pathogenesis of MS and examines the role of gut-oriented interventions in MS.