This article discusses the subject of causation (etiology) as it has been applied to the field of temporomandibular disorders (TMD). These disorders have been the focus of considerable disagreement about what constitutes proper diagnosis and treatment, and it is clear that the main basis for these controversies has been conflicting views about the etiology of the various disorders. Many earlier theories emphasized dental morphological factors of malocclusion, occlusal dysharmony, and bad mandibular alignment as being primarily responsible for the development of TMD symptoms. Certain versions of these dental/skeletal concepts have long been a part of the belief system of the orthodontic specialty, leading to some special orthodontic protocols for managing TM disorders. Today, it is generally agreed that the etiology of TM disorders includes a multifactorial combination of physical and psychosocial factors, with some of them being either poorly understood or difficult to assess. In most cases, there are no special occlusal or orthodontic factors to be considered, and therefore occlusion-changing procedures are not generally required for successful treatment. This means that contemporary orthodontists must face the same challenge as all their other dental colleagues: to learn about modern concepts of diagnosis and treatment for all types of orofacial pain patients, and then to use currently recommended protocols for pain management and musculoskeletal therapy for those patients who have temporomandibular disorders.