Radiodermatitis (radiation dermatitis, radiation-induced skin reactions, or radiation injury) is a significant side effect of ionizing radiation delivered to the skin during cancer treatment as well as a result of nuclear attacks and disasters, such as that which occurred in Fukushima in 2011. More specifically, 95 % of cancer patients receiving radiation therapy will develop some form of radiodermatitis, including erythema, dry desquamation, and moist desquamation. These radiation skin reactions result in a myriad of complications, including delays in treatment, diminished aesthetic appeal, and reduced quality of life. Recent technological advancements and novel treatment regimens have only been successful in partly ameliorating these adverse side effects. This article examines the current knowledge surrounding the pathogenesis, clinical manifestations, differential diagnoses, prevention, and management of radiodermatitis. Future research should examine therapies that incorporate the current understanding of the pathophysiology of radiodermatitis while measuring effectiveness using objective and universal outcome measures.