Pelvic radiation is increasingly being used for the neoadjuvant and definitive treatment of pelvic organ malignancy. While this treatment can be highly effective, and may assist in organ sparing, it is also associated with significant toxicity and devastating adverse events that need to be considered. In broad terms, pelvic radiation disease affects both the primary target organ as well as adjacent organs and soft tissue structures, with complications that can be classified and graded according to consensus criteria. The complication grade is often modality, dose, and area dependent. The most common manifestations are proctitis, cystitis, recto-urethral fistula, ureteric stricture, and bone involvement. Toxicity can be misdiagnosed for many years, resulting in significant management delays. Complications can be difficult to prevent and challenging to treat, requiring specialized multi-disciplinary input to achieve the best possible strategy to minimize impact and improve patient quality of life.