The name Kayleigh is a variant of Kaylee, which itself is derived from the Irish name Caoilainn, meaning 'slender' or 'fair'. The spelling 'Kayleigh' gained significant popularity due to the 1985 song by the British neo-prog band Marillion, which was released as the first single from their concept album Misplaced Childhood. The song's success in the UK and internationally helped popularize this particular spelling of the name.