Stuart Wellford Cook (April 15, 1913—March 25, 1993) was an American social psychologist known for his research on the societal effects of racism and religious intolerance. He is particularly known for a study he conducted with Isidor Chein and Kenneth Bancroft Clark on the psychological effects of racial segregation. This study was cited by the appellates in the 1954 landmark United States Supreme Court case Brown v. Board of Education. His research also focused on many other psychological subjects, including clinical psychology, military psychology, and psychological research methods.