Myofunctional therapy （MFT） has been developed as a therapy for correction of tongue thrust swallowing to facilitate successful orthodontic treatment. It has also been developed as a therapy for improving inharmonious functions of the orofacial muscles, including placing the tongue and lips in their proper positions at rest. In addition, MFT is expected to be used not only in the field of orthodontics but also for promoting oral function in children as well as preventing oral frailty in the elderly. Moreover, since orthodontic treatment has attracted attention as an adjunct therapy for obstructive sleep apnea in pediatrics, oral function has started to gain interest as well. Several reports describing the effects of MFT have been published. MFT is considered to be highly useful as a complementary non-invasive therapy. However, the mechanism of action by which MFT, which is training performed while awake, effectively improves breathing during sleep remains unclear. Moreover, regarding the subjects, objectives, instruction details, and duration, MFT performed on pediatric obstructive sleep apnea （OSA） differs from that performed in the field of orthodontics. In order to perform MFT on OSA effectively, this article examines the conventional MFT that has been performed in orthodontic patients and describes a series of studies on the current state of MFT in pediatric OSA, and suggests necessary action to perform MFT on pediatric OSA in the future in Japan.