Martin Theodore Orne (October 16, 1927, Vienna, Austria – February 11, 2000, Paoli, Pennsylvania) was a professor of psychiatry and psychology at the University of Pennsylvania.
Orne is best known for his pioneering research into demand characteristics, illustrating the weakness of informing participants that they are taking part in a psychology experiment and yet expecting them to act normally.
He was well known as a researcher in the field of hypnosis and is also noted for his involvement with the poet Anne Sexton, and with the trials of Patty Hearst and Kenneth Bianchi.