"Killer on the Loose" is a song by the Irish rock band Thin Lizzy, written by Phil Lynott, released as a single in September 1980. It was a chart hit, peaking at No.10 in the UK and No.5 in Ireland. It later appeared on their 1980 album Chinatown.
The song, in which Lynott took the persona of Jack the Ripper, received much controversy. The single was released amidst the Yorkshire Ripper murders and many members of the British public, largely women, were outraged by the songs lyrics and its references to the Ripper. A music video, in which Lynott is dressed in a Ripper style trench coat surrounded by scantily clad women, generated even more controversy when it was released in 1980.