石橋優子 (Yuuko Ishibashi, born April 3, 1980) is a Japanese soprano from Tokyo whose vocal range is said to be 4 octaves. Her songs are mainly acoustic and include genres such as folk (sometimes noticeably influenced by shimauta), neoclassical or jazz. Previously known as YOU-CO, and currently signed under Across Entertainment, she has contributed to many video game soundtracks such as Ar tonelico and Atelier Iris Grand Fantasm.

Read more about 石橋優子 on Last.fm.