Kayleigh is a modern English name that joins Kay with the surname ending -leigh; it is usually explained as a form of Kaylee, or linked to the Irish surname Caollaidhe, "slender". The 1985 hit single Kayleigh by the band Marillion made the spelling popular in Britain before it spread to the United States. Kayleigh ranked number 349 in 2000, peaked at number 227 in 2009 and has dropped to number 804 in 2025.