The purpose of this study was to investigate the effects of coed exercise on social physique anxiety (SPA), body image (BI), and self-esteem (SE). SPA is the concern that others are negatively evaluating one’s body or physical appearance, and is strongly related to BI and SE. Although once believed to be stable traits, SPA, BI, and SE are now recognized to vary between situations; therefore, it is reasonable to assume that different exercise environments could influence these variables. Students in pre-established physical education courses completed pre and post- questionnaires and were categorized into a single-sex, minority-sex, majority-sex, or equal-sex categories based on the number of males and females enrolled. Results indicated that SPA decreased over time in an exercise program among females, but no differences were found based on the presence of the opposite sex. However, among males, differences in BI were observed based on class categorization and time spent in an exercise program.