Masayo Sawada, better known by her stagename Sister MAYO, is a Japanese singer. She is a member of the Columbia Music Entertainment duo Cyber Nation Network, and a vocalist in Project.R which performs many theme songs for the Super Sentai series, some have reached the top ten in Oricon's charts. Her best-known songs as a soloist have been the opening theme of Haré+Guu and the ending theme of Mahou Sentai Magiranger. She is the younger sister of heavy metal musician Taiji, with whom she was in the rock band Otokaze.
After attending vocational school, she got a job at a travel agency. After suffering from a herniated disc, she decided to pursue her dream of being a musician. She released her first single in 1997 under her own name. A producer gave her her stage name when she joined Cyber Nation Network.
In appearances, she generally wears a baseball cap. Prior to the release of "Jumon Kōrin ~ Magical Force", she also wore glasses, out of shyness. Nippon Columbia asked her to take off one or the other, and she decided to keep the cap.
In 2020, she started the unit Rainbow☆MAG!C with Hideyuki Takahashi and Natsuo.