Duplicity is a 1781 comedy play by the British writer Thomas Holcroft. The original Covent Garden cast included John Henderson as Mr Osborne, William Thomas Lewis as Sir Harry Portland, as Sir Hornet Armstrong, Charles Lee Lewes as Squire Turnbull, John Edwin as Timid, as Mr Vandervelt, as Scrip, Sarah Maria Wilson as Miss Turnbull, Elizabeth Inchbald as Melissa, Ann Pitt as Mrs Trip and Elizabeth Younge as Clara.