Radiation oncology is one of the more technologically sophisticated fields in medicine, requiring close collaboration between physicians, technologists, and medical physicists. High-profile errors in this field have been attributed to rapidly changing technology and human factors, and this review sought to characterize the types and frequency of errors and near misses in routine radiotherapy practice using data from voluntary error databases as well as published literature. Although the overall incidence of errors appears low, most reported errors were considered preventable, as they occurred due to faulty information transfer. The authors discuss the types of errors that may occur at each stage of radiotherapy and recommend error prevention strategies.