Diarmuid O'Hegarty (Irish: Ó hÉigeartuigh; 1892–1958) was an Irish civil servant and revolutionary. O’Hegarty was a member of the Irish Volunteer executive (June 1916 – November 1921), IRA director of communications (July 1918 – March 1920), and director of Organisation (March 1920 – April 1921). Diarmuid O’Hegarty was an extremely self- effacing man; he was described by Frank Pakenham as the ‘civil servant of the revolution’.