"You've Got My Number (Why Don't You Use It?)" is a 1979 punk rock song originally written and recorded by Northern Irish band The Undertones. Written in the summer of 1979 by the band's main songwriter, John O'Neill, the single was released on 9 October that year and reached number 32 in the UK charts. The song was performed on Top of the Pops on 15 November 1979.