Illusion were a British progressive rock band formed in 1977. They released two albums, Out of the Mist (1977) and Illusion (1978) on Island Records, before folding in 1979. A third release titled Enchanted Caress (made up of demos for a proposed 3rd album, from the late 1970s) was released in 1990.

Illusion were intended to be a reunion of the original line-up of Renaissance (whose second 1971 album was titled Illusion), but singer and guitarist Keith Relf died before the project was realised. Thereafter, the band's new lineup featured Louis Cennamo on bass, John Hawken on keyboards, Jim McCarty moved from drums to play acoustic guitar and share vocals with Jane Relf, while Eddie McNeill replaced him on drums and John Knightsbridge (from Third World War, and later of Ruthless Blues) played lead guitar.

In 2001, McCarty, Cennamo, Hawken and Jane Relf reunited once again to record Through the Fire, an album of new material, under the bandname Renaissance Illusion.