Masami Okui (奥井 雅美, Okui Masami?), born March 13, 1968) is a J-Rock/J-Pop singer who was born in Itami, Hyōgo Prefecture. She began her professional musical career at age 21 as a concert backup singer. From almost the very beginning of her career, Masami has sung themes for anime tv and movies. She is especially well known for her songs from Revolutionary Girl Utena, Slayers, Sorcerer Hunters, Di Gi Charat, Magic User's Club, Jungle de Ikou, Akihabara Dennou Gumi, Ray the Animation, He Is My Master and Yu-Gi-Oh! Duel Monsters. She has performed material for more than 50 singles and 20 albums to date (including her work with JAM Project and Chihiro Yonekura).