Graft-vs-host disease (GVHD) is a multisystem disease that arises as a complication of allogeneic hematopoietic stem cell transplant. It is due to recognition of the recipient's tissues by immune cells from the donor. The skin and mucous membranes are the organs most commonly affected. GVHD is classified as acute or chronic depending on the pathophysiology and clinical presentation. Acute GVHD typically presents with the triad of rash, diarrhea, and hyperbilirubinemia, and treatment is based on systemic corticosteroid and immunosuppressant therapy. The cutaneous manifestations of chronic GVHD are divided into sclerodermiform and nonsclerodermiform, and the mucous membranes and skin appendages may also be affected. The diagnosis is mainly clinical, but skin biopsy can help in doubtful cases. Treatment can be topical, systemic, or physical, depending on the size, site, and depth of the lesions and the involvement of other organs.