Aim The original indication for rapid palatal expansion was to treat skeletal maxillary constriction. As positive effects were clinically proven, the number of indications for rapid palatal expansion has continuously grown. The purpose of the present article was to review the literature and to evaluate the effect of rapid palatal expansion on nose breathing, natural head position, obstructive sleep apnoea syndrome, nocturnal enuresis and conductive hearing loss. Conclusion It can be concluded that rapid palatal expansion is predominantly recommended in children with maxillary constriction. In those with normal occlusion, maxillary expansion can be considered as the really last choice of treatment when other treatment options in patients with nose breathing, obstructive sleep apnea syndrome (OSAS), nocturnal enuresis and conductive hearing loss (CHL) have failed. Therefore, collaboration between paediatricians, otolaryngologists, paediatric dentists and orthodontists will lead to the best treatment outcomes in the future.