Multiple sclerosis (MS) is considered the most common autoimmune demyelinating disease targeting the central nervous system (CNS). The etiology of MS remains largely unknown, and there is still no curative treatment. The current treatments, targeting the immune system, are effective in early relapsing MS but not in chronic progressive MS. Furthermore, infections are a major concern in the context of the current immunomodulatory treatments of MS. Therefore, therapeutic strategies beyond targeting the immune system are desirable. Blood–brain barrier (BBB) is a potential therapeutic target in MS, since BBB breakdown is an early hallmark of MS, and there is accumulating evidence that BBB dysfunction is also associated with progressive MS. For understanding the specific involvement of BBB dysfunction in MS pathogenesis, suitable BBB in vitro models are required. Here, we summarize current evidence of BBB alterations in MS and the in vitro BBB models allowing to study those BBB alterations and their contribution to MS pathogenesis.