Macroglossia is observed in the majority of patients with Beckwith-Wiedemann syndrome (BWS), a congenital condition with characteristic anomalies. In addition, sleep disordered breathing (SDB) associated with macroglossia has occasionally been noted in BWS patients, for which tongue reduction surgery is generally performed. However, macroglossia is related to various health problems, such as eating and articulation disorders, attention deficit disorder, enuresis, and thorax deformation, as well as aesthetic issues. Therefore, in addition to treating airway obstruction, tongue reduction surgery can also exert favorable effects on the overall quality of life (QOL) of patients. However, surgical indications for tongue reduction have yet to be established and reports on QOL assessments after surgery are rare. The OSA-18 questionnaire is used for screening SDB and is also useful for assessing the effect of tongue reduction surgery on QOL. We report a patient whose QOL was improved by tongue reduction surgery. On the basis of our patient's results, we recommend tongue reduction surgery in early childhood not only to treat SDB but also to improve QOL.