Abstract : Vitamin D is well known for its beneficial effects on phosphocalcic homeostasis. The discovery of the role of vitamin D in cancers, infections, cardiovascular or autoimmune pathologies have promoted interest for this molecule. Skin and vitamin D are closely related. The skin is not only the site of vitamin D synthesis, but also a target organ as calcitriol plays an important hormonal and regulatory role, acting on cell proliferation, differentiation and immunomodulation. Furthermore, vitamin D influences the incidence and therapeutic response of certain dermatoses. In addition, many medical situations, mainly dermatological, require strict photoprotection and may therefore indirectly be responsible for a vitamin D deficiency in patients. The current role of vitamin D in skin cancers, inflammatory and autoimmune skin diseases is summarized.