Radiation-induced toxicity is a major cause of long-term disability after cancer treatment. Radiation fibrosis describes the insidious pathologic fibrotic tissue sclerosis that can occur in response to radiation exposure. Radiation fibrosis syndrome describes the myriad clinical manifestations of progressive fibrotic tissue sclerosis resulting from radiation treatment. Radiation-induced damage can include "myelo-radiculo-plexo-neuro-myopathy," causing muscle weakness and dysfunction and contributing to neuromuscular injury. Similarly, radiation damage to neuromuscular structures contributes to radiation-induced trismus and cervical dystonia in head and neck cancer survivors. This narrative review discusses the pathophysiology, anatomy, evaluation, and treatment of neuromuscular, musculoskeletal, and functional disorders that can result as late effects of radiation treatment. Rehabilitation medicine physicians with extensive training in neuromuscular and musculoskeletal medicine as well as in the principles of functional restoration are uniquely positioned to help lead efforts to improve the quality of life for cancer survivors with radiation fibrosis syndrome.