Body dissatisfaction is experienced by individuals in all weight classes and has been linked with poor mental and physical health outcomes in both women and men. Exercise interventions are a common tool used to improve body dissatisfaction, but their impact is relatively small. Reasons for this small impact might include high rates of attrition and difficulty in recruiting those who are most sedentary in the first place, or who avoid exercise (at most high-risk/high-need). The present study evaluates the extent to which exercise avoidance mediates the association of body dissatisfaction with exercise frequency and whether perceived embarrassment, exercise fatigue, and exercise self-efficacy explain the association of body dissatisfaction with exercise avoidance. Participants were 110 students and staff from an urban, private US university. Body dissatisfaction, exercise avoidance, and hypothesized mediators were measured at baseline; objective exercise was measured with accelerometers for one month. Exercise avoidance mediated the relation between body dissatisfaction and exercise frequency (B = -.02 (SE =.01) [95% CI: -.04 to -.01]). Additionally, the relation between body dissatisfaction and exercise avoidance was fully mediated by embarrassment (B = .24 (SE .10) [95% CI: .08 to .47])and fatigue (B = .10 (SE .06) [95% CI: .01 to .28]) but not by self-efficacy (B = -.00 (SE .02) [95% CI: -.06 to .01]). Thus, exercise interventions may not effectively target individuals who are dissatisfied with their body because they may be avoiding exercise due to perceived embarrassment and fatigue.