Temporomandibular disorder (TMD) is a term describing musculoskeletal conditions of the face, jaw and temporal regions. TMD is frequently associated with pain and/or dysfunction such as impaired jaw function, pain in the temporomandibular joint (TMJ), muscles and/or related structures, and associated headaches. The etiology of TMD is multifactorial and complex. It is known that one cause of TMD symptom development is treatment for head and neck cancer (HNC). The main treatment modalities for HNC include radiotherapy (RT) with or without chemotherapy and surgical intervention, as either a single therapy or a combination therapy. In the head and neck region, the anatomical structures are necessary for essential functions such as speech, swallowing, breathing, smell, and taste. The treatment of head and neck tumors may frequently impair some of these functions, which may result in pain, oral dysfunction, and impaired health-related quality of life.