Air Marshal Sir Christopher Nigel Harper, KBE (born 25 March 1957) is a senior Royal Air Force officer, who served as the UK Military Representative to NATO and the European Union from 2011 to 2013 and as Director General of the NATO International Military Staff from 2013 to 2016. He was previously Deputy Commander Allied Joint Force Command at Brunssum in the Netherlands (2009–11), and Air Officer Commanding No. 1 Group in the UK (2007–09).