Multiple sclerosis (MS) is a chronic autoimmune, inflammatory, and neurodegenerative disease that affects the central nervous system (CNS). MS is characterized by immune dysregulation, which results in the infiltration of the CNS by immune cells, triggering demyelination, axonal damage, and neurodegeneration. Although the exact causes of MS are not fully understood, genetic and environmental factors are thought to control MS onset and progression. In this article, we review the main immunological mechanisms involved in MS pathogenesis.