John Edward Illsley (born 24 June 1949) is an English musician, best known as bassist of the rock band Dire Straits. He has received multiple BRIT and Grammy Awards, and a Heritage Award.
As one of the founding band members, alongside drummer Pick Withers and guitarist brothers Mark Knopfler and David Knopfler, Illsley played a role in the development of Dire Straits' sound.