Mikio Sakai is a Japanese singer-songwriter and composer from Hokkaidō, born on August 24, 1970. He is signed to Toy's Factory and has worked under his own name and under his real name, Mikirou Sakai (酒井 幹郎).
Sakai made his debut with the single "Ima dake wa Kimi wo Hanasanai." and later became known for anime and related media music. His credits include songs and compositions for Fantastic Children, Tsubasa Chronicle, the Gorou Taniguchi-directed Sunrise productions, Planetes, s-CRY-ed, and Code Geass, along with other media. His writing often moves between melodic Japanese pop and soundtrack-oriented arrangements, which makes him a familiar name for listeners looking for anime songs and anison-related work.