The mid-twentieth-century Harvard sociologist Talcott Parsons is seldom, if ever, depicted as a social psychologist. Yet, toward the end of his career, he declared that he had done a good deal of work in that field, particularly in regard to the study of mass phenomena. In this article I examine Parsons’s social psychology of mass phenomena and demonstrate that it was greatly influenced by Freudian conceptualizations. I first consider Parsons’s comments on what he saw as the place of social psychology in sociological theory. Next, I discuss several terms that were crucial to his social psychology. I then probe two of Parsons’s articles that provide conceptual context to his writings on deviant collective behavior. Following that, I closely examine Parsons’s studies where he analyzed the mass phenomena of Nazism and antisemitism. Finally, I conclude that between 1940 and 1947 Parsons produced a comprehensive psychoanalytic social psychology.