Gastroesophageal reflux (GER) is commonly associated with several types of respiratory symptoms in adults and children, but it is not always clear whether respiratory disease associated with reflux (RDAR) is caused by GER or vice versa. There is strong clinical and experimental evidence that apnea and apparent life-threatening events can be caused by laryngospasm secondary to aspiration of refluxed gastric contents, and it is also likely that GER is a common cause of recurrent croup and stridor. Although GER is commonly associated with asthma and infantile wheezing, its role as a cause of lower respiratory tract disease is poorly defined, and the mechanism of pathogenesis is unclear. The pH probe is commonly considered the gold standard for diagnosing GER, but its validity lies in its correlation with esophagitis and its accuracy in the diagnosis of RDAR is unknown. Medical treatment of GER typically consists of a combination of acid-blocking and prokinetic agents, which is often but not uniformly successful in controlling GER and RDAR. This review discusses the clinical association of various respiratory conditions with GER, clinical and experimental data on pathogenesis, controversies in diagnosis and treatment, and the reasons for the current difficulties in clearly defining the spectrum of respiratory disease associated with reflux.