Most universities today require their students to learn about diversity as a part of their degree. Research has examined the effectiveness of diversity courses at changing attitudes toward groups, focusing on sexism or racism, within psychology and women’s studies disciplines. Given the increasing concern over bias in policing, however, this diversity training may be of importance to the study of criminal justice. The current study aims to examine the effectiveness of a diversity course within a criminal justice program at changing perceptions of groups using a survey based on validated measures of attitudes toward women, homosexuality, and symbolic racism. Change in attitudes between the pre-test and post-test are examined. Results suggest that the course is effective at changing attitudes toward homosexuality, but not race or sex. The results also suggest that these perceptions are dependent on group characteristics.