Aerophagia is defined as a disease that causes chronic belching, nausea, and abdominal distention due to excessive air swallowing. The patient was a 10-year-old boy who complained of chronic abdominal distention and pain by aerophagia. The abdominal symptoms had worsened after fundoplication surgery. A nasogastric tube was placed to release the gas accumulated in the stomach. Frequent abnormal swallowing and tongue thrust were observed at the first visit to our clinic. Upon swallowing, his tongue protruded between the front teeth, and his orbicularis and mentalis muscles showed a dysfunctional pattern. We diagnosed abdominal distention and pain by aerophagia due to orofacial myofunctional disorders. Therefore, oral myofunctional therapy (MFT) was used to address these problems and to correct the improper function of the tongue and orofacial muscles. MFT improved the function of his orofacial muscles and this improvement led to a reduction of abnormal air swallowing. Five months later, the nasogastric tube was removed. In addition, his occlusal condition had also improved. MFT may be a useful technique for alleviating aerophagia due to orofacial myofunctional disorders.