Obesity is a worldwide major public health problem with an alarmingly increasing prevalence over the past 2 decades. The consequences of obesity in the skin are underestimated. In this paper, we review the effect of obesity on the skin, including how increased body mass index affects skin physiology, skin barrier, collagen structure, and wound healing. Obesity also affects sebaceous and sweat glands and causes circulatory and lymphatic changes. Common skin manifestations related to obesity include acanthosis nigricans, acrochordons, keratosis pilaris, striae distensae, cellulite, and plantar hyperkeratosis. Obesity has metabolic effects, such as causing hyperandrogenism and gout, which in turn are associated with cutaneous manifestations. Furthermore, obesity is associated with an increased incidence of bacterial and Candida skin infections, as well as onychomycosis, inflammatory skin diseases, and chronic dermatoses like hidradenitis suppurativa, psoriasis, and rosacea. The association between atopic dermatitis and obesity and the increased risk of skin cancer among obese patients is debatable. Obesity is also related to rare skin conditions and to premature hair graying. As physicians, understanding these clinical signs and the underlying systemic disorders will facilitate earlier diagnoses for better treatment and avoidance of sequelae.