Described and illustrated by Allan G. Brodie in 1946, Brodie's syndrome corresponds to an abnormal transverse occlusal relationship in which the palatal cusps of the upper molars lie outside the vestibular cusps of their mandibular antagonists. This article covers the diagnosis, clinical presentation, etiology (and, particularly, etiopathogenesis) and evolution of this syndrome, and also its management, which is often difficult. The main limitations and difficulties of orthodontics and surgery are presented, along with the surgical techniques used. These points are illustrated by some clinical cases highlighting the importance of three-dimensional analyses and 3D planning.