Gastroesophageal reflux (GER) is a common problem among infants and young children. The symptoms of GER in children with major developmental disabilities or neurologic impairment are often more severe and/or persistent than in other children. This article reviews the anatomy and physiology of the upper gastrointestinal tract and discusses the potential causes of GER in young children, especially those with major developmental disabilities or neurologic impairment. In addition, the signs, symptoms, and complications of GER in young children and the association between GER and recurrent or chronic respiratory symptoms are presented. The authors also discuss the various diagnostic tests used to aid in the diagnosis of GER in young children, their theoretical and practical utility, and their limitations. Finally, there is a discussion of the therapeutic options for GER in young children including positioning, dietary and feeding manipulations, medications, and surgery.