Kate Victoria Tunstall (born 23 June 1975), known by her stage name KT Tunstall, is a Scottish singer-songwriter and musician. She broke into the public eye with a 2004 live solo performance of her song "Black Horse and the Cherry Tree" on Later... with Jools Holland.

Born in Edinburgh as an illegitimate child of a Hong Kong-born exotic dancer, she was adopted by David and Rosemary Tunstall of St Andrews. She attended the Lawhead Primary and Madras College in St. Andrews, High School of Dundee and Kent School in New England. She earned her BA in Drama & Music in 1996 from the Royal Holloway, University of London, which conferred her an honorary doctorate in 2011. At the age of four she started playing piano, and later other musical instruments.

Inspired by childhood experiences at her foster father's physics laboratory at University of St Andrews, her debut album was named Eye to the Telescope. Released in 2004, this album marked her success in music career. It earned her nominations for the Mercury Prize in 2005, BRIT Award for Best British Live Act and BRIT Award for Best Breakthrough Act in 2006, and Grammy Award for Best Female Pop Vocal Performance in 2007. She eventually won BRIT Award for Best British Female Artist and European Border Breakers Award, both in 2006. The single "Black Horse and the Cherry Tree" was given the Q Magazine Award for Best Track in 2005, and Suddenly I See won the Ivor Novello Award for Best Song in 2006. Suddenly I See became a popular hit and has been featured in The Devil Wears Prada, Blind Dating, Ugly Betty, Grey's Anatomy, Love, Rosie, Thrillville, and as a campaign song of the US presidential campaign of Hillary Clinton in 2008.

She has released five albums internationally: Eye to the Telescope (2004), KT Tunstall's Acoustic Extravaganza (2006), Drastic Fantastic (2007), Tiger Suit (2010) and Invisible Empire // Crescent Moon (2013). She has also appeared in two episodes of the comedy series This is Jinsy on Sky Atlantic. Since 2013, she has been working with American artist Howe Gelb.

Tunstall has written soundtracks for films: "Boy" from The Kid, "Miracle" for Winter's Tale, "We Could Be Kings" for Million Dollar Arm, "Float", "Strange Sight" and "1000 Years" for Tinker Bell and the Legend of the NeverBeast, and "Fit In" for About Ray.