Elevated body dissatisfaction is underpinned by an attentional bias towards images portraying appearance ideals. However, very little is known about the specific attentional mechanisms and mediating factors involved in this relationship in the context of male body dissatisfaction. The present study sought to replicate and extend on previous research among women showing that the relationship between attentional engagement bias and body dissatisfaction is sequentially mediated by appearance comparisons and rumination. Seventy undergraduate males completed an attentional task capable of independently assessing biased attentional engagement with images of muscular and non-muscular bodies followed by self-report measures of appearance comparisons, eating disorder-specific rumination, and body dissatisfaction. Results revealed that a heightened tendency to engage in appearance comparisons was associated with increased attentional engagement with muscular bodies, relative to non-muscular bodies. Moreover, a serial mediation analysis revealed that increased attentional engagement with muscular bodies was associated with appearance comparisons, which in turn were associated with eating disorder-specific rumination and, consequently, body dissatisfaction. The current findings replicate among men the serial mediation model of body dissatisfaction previously described among women and implicate heightened attentional engagement with idealized images as a potential pathway to body dissatisfaction in men.