Gastroesophageal reflux (GER) is a potential trigger of asthma. GER symptoms are more prevalent in asthma patients compared with control populations, with a prevalence of approximately 75%. GER symptoms are associated with respiratory symptoms and inhaler use. GER may also occur without esophageal symptoms. Abnormal esophageal acid contact times are also more prevalent in patients with asthma compared with control populations, with a prevalence of 80%. Pathophysiologic mechanisms of esophageal acid-induced bronchoconstriction include a vagally mediated reflex, heightened bronchial reactivity, and microaspiration. Esophageal acid may increase minute ventilation without evidence of bronchoconstriction. Esophageal acid is associated with the release of substance P in the bronchial mucosa, resulting in airway edema. Medical antireflux therapy with proton pump inhibitors results in asthma symptom improvement in approximately 70% of patients, similar to surgical results. Predictors of asthma response include the presence of regurgitation, proximal acid reflux, esophagitis healing with therapy, reflux-associated respiratory symptoms, or nocturnal asthma. Management of GER in adult patients with asthma should include a 3-month trial of high-dose proton pump inhibitor while monitoring asthma outcome. GER should be considered as a potential asthma trigger in all patients.