Ø was a pseudonym used by Mika Vainio (born 1963, Helsinki, Finland - died 12 April, 2017, France, aged 53) a Finnish electronic musician, composer and producer.

He began his musical career playing electronics and drums as part of the early Finnish industrial and noise scene. In 1993, together with Ilpo Väisänen and Sami Salo, he founded the minimal electronic group Pan Sonic. Sami Salo left Pan Sonic in 1996 and the project continued as a duo until disbanding in 2009. Vainio then established a successful solo career, often collaborating with experimental French composer Franck Vigroux.