Sebastian de Grazia (1917–2000) was an American author.
Born in Chicago, he received his bachelor's degree and a doctorate in political science from the University of Chicago.
During World War II he served in the Office of Strategic Services, predecessor to the Central Intelligence Agency, as an analyst.
From 1962 to 1988 he taught political philosophy at Rutgers University.
He received the 1990 Pulitzer Prize for Biography or Autobiography for his 1989 book Machiavelli in Hell.
He is also the author of The Political Community (1948), Errors of Psychotherapy (1952), Of Time, Work, and Leisure (1962), and A Country with No Name (1997).