Growing evidence suggests a pivotal role for vitamin D in cancers, particularly melanoma. The broad immunologic effects of vitamin D and its signaling axis make for a complex interplay between tumor cells and the immune system. Preclinical evidence suggests vitamin D to have protective effects in melanoma oncogenesis and progression, creating a potential role for vitamin D supplementation in cancer prevention and/or adjuvant therapy. In this commentary, the authors highlight studies of vitamin D in melanoma with clinical implications and call for large clinical trials to definitively determine the role of supplementation in patients to prevent and help treat melanoma.