The pathophysiology of Gastroesophageal reflux disease (GERD) has been known that it is developed when the offense-primarily the gastric acid-pepsin content of the refluxate-overcomes a 3-tiered esophageal protective defense. consisting of antireflux mechanisms, luminal clearance mechanisms, and tissue resistance. Laryngopharyngeal reflux (LPR), which is known as an extraesophageal variant of GERD, has been considered to be developed by transient lower esophageal sphincter relaxation (TLESR), direct mucosal injury by gastric contents, more sensitive mucosa compared to esophagus, and absence of buffering effect and aggravation of the injury due to pepsin. However, hypothesis of the pathophysiology in both entities are numerous and still lack of understanding for being a theory. There is no conflict that understanding the pathophysiology is necessary for resolving the problems of these diseases and numerous studies and results have been releasing. This review could provide clinicians dealing with GERD and LPR with applicable new information and help for overcoming the clinical obstruction.