Radiation-induced lumbosacral plexopathy (RILP) is a rare but severely debilitating side effect of abdominopelvic irradiation, which is used in the management of a myriad of primary and metastatic tumors involving the abdominal, pelvic and retroperitoneal regions. Although the exact mechanism of RILP is not yet clearly elucidated, postulated mechanisms include radiation-induced vascular injury and radiation fibrosis leading to axonal damage and entrapment of nerves/small vessels, respectively. Effects of radiation are suggested to be correlated to the dose per fraction and total dose of radiation therapy (RT), use of radiosensitizing agents, RT technique, and concurrent administration of chemotherapy. Furthermore, the risk of RILP occurrence particularly increases with intracavitary and intraoperative brachytherapy applications. In the current review, we aimed to summarize the latest literature considering aspects of the pathophysiology, clinical features differential diagnosis, and treatment of this debilitating complication.