These three studies sought to better understand experiences of body-related envy and to examine the association with motivation and exercise behavior in young adult males and females. In an interview study, participants ( N = 11) discussed body-related envy within a framework of social comparison. In Study 2, a thematic content analysis was conducted on self-reported narratives of body-related envy experiences reported by 288 participants. Themes of body-related envy triggers, cognitions, and cognitive and behavioral outcomes were identified. Findings from Studies 1 and 2 highlighted the possible link between body-related envy and exercise motivation and behavior. Study 3 tested these associations with males and females ( N = 595) who completed a self-report questionnaire. In the structural equation model, body-related envy was positively associated with external, introjected, and identified regulations, and identified regulation was positively associated with exercise behavior. Taken together, the importance of body-related envy in the experience of cognitive, affective, and behavioral outcomes related to sport and exercise contexts is highlighted.