David O'Sullivan (born 1 March 1953) is the Director General of the Institute of International and European Affairs (IIEA). He was previously a European civil servant served as Ambassador of the European Union to the United States from 2014 to 2019, Chief Operating Officer of the EEAS from 2010 to 2014, Director-General of DG RELEX from October 2010 to December 2010, Director-General of DG Trade from 2005 to 2010, Secretary General of the European Commission from 2000 to 2005.