Myoitsu (728 - April 21, 798) was a Buddhist monk from the Nara period to the early Heian period. His secular surname was Oya. He came from Oyakori Village, Soekami County, Yamato Province.
He studied under Jikun (also known as Jikin) in Todai-ji Temple. In 753, he served as an instructor in a sutra Urabonkyo at Todai-ji Temple, and in 780, he served as an instructor of the Yuimae, a religious service. When Gyoga returned from Tang in 782, he questioned Gyoga about the sect's doctrine and criticized his studies severely. The reason for this is said to be that, having stayed in Tang for over 30 years, Gyoga was unable to make himself understood in Japanese. Around this period, Myoitsu operated Todaiji Temple as a high-ranked monk called Joza among the administrative positions called Sango, and in 794, he served as one of monks called Shokushu to take part in the memorial service of the main building Konponchudo in Mount Hiei. It has been said that in his late years, he married and because of that, he lost his reputation.