Louis Clark (27 February 1947 – 13 February 2021) was an English music arranger and keyboard player renowned for his work with the Electric Light Orchestra (ELO) and the Hooked on Classics series. Born in Kempston, Bedfordshire, England, Clark trained at Leeds College of Music and began his musical career as a bass guitarist for the Birmingham band The Buccaneers, which evolved into Monopoly and eventually The Raymond Froggatt Band.

Clark's significant contribution to ELO began in 1974 with the album Eldorado, where he served as the conductor and arranger for the orchestra and choir, collaborating with Jeff Lynne and Richard Tandy on string arrangements for several albums including Face the Music, A New World Record, Out of the Blue, Discovery, and Xanadu. He also played synthesizers during ELO's Time tour and contributed to the Secret Messages album in 1983. Clark was a key figure in ELO Part II and its successor, The Orchestra, remaining active with the group until his passing.

In addition to his work with ELO, Clark was associated with the Royal Philharmonic Orchestra (RPO), arranging music for Renaissance's concert at the Royal Albert Hall and conducting the RPO for the successful Hooked on Classics series in the early 1980s. He also released albums with the RPO covering music by Queen and The Beatles.

Clark's versatility extended to composing library music for television, commercials, and radio, with notable work for Bruton Music. He arranged strings for the film The Apple, which gained cult status despite initial critical derision.

In 2011, Clark became president of the English Pops Orchestra, revisiting his Hooked on Classics work with live performances. Louis Clark passed away on 13 February 2021 in Elyria, Ohio, at the age of 73, leaving a legacy of bridging classical and popular music.