Without realizing it, orthodontists may find themselves treating patients suffering from cranio-mandibular disorders, who may be adults, but not necessarily. Both young children and adolescents can also have these problems. Orthodontists often fall into the trap of not recognizing these disorders especially when the clinical signs are discreet or even non-existent. In order to save orthodontists from encountering unpleasant post-treatment surprises, we present in this paper a review of some of the indications of the etiology of craniomandibular dysfunction, how to diagnose it, and the importance of its major clinical signs that can be a great help to them in achieving a keener state of vigilance in this regard throughout orthodontic therapy.