Increasing evidence suggests that sedentary behaviour is associated with a variety of negative health consequences, and that physical activity cannot eliminate the effects of sedentary behavior (Temmel & Rhodes, 2013). Thus, it is important to investigate the correlates of sedentary behaviour. Body-related variables are consistently related to physical activity, with greater levels of physical activity associated with a more positive body image (Campbell & Hausenblas, 2009). Purpose: To investigate whether body-related variables could predict both physical activity and sedentary behaviour. Methods: Participants (157 college females) completed measures of physical activity, sedentary behaviour and several body-related variables. Results: Sedentary behaviour and physical activity were unrelated. Self-presentational efficacy, drive for muscularity, body dissatisfaction and self-objectification were correlated with physical activity. Social physique anxiety and drive for muscularity were correlated to sedentary behaviour. Regression analysis demonstrated that self-presentational efficacy and drive for muscularity were significant predictors of physical activity (accounting for nearly 11% of the variance), while a combination of social physique anxiety and drive for muscularity predicted sedentary behaviour, with social physique anxiety accounting for a greater amount of the variance. Conclusion: This study supports the contention that physical activity and sedentary behaviour are distinct constructs. Therefore, the ways in which we promote physical activity should differ from the ways in which we discourage sedentary behaviour. Body-related variables appear to predict both physical activity and sedentary behaviour. Future directions may involve investigating why the drive for muscularity was the only variable related to both sedentary behaviour and physical activity.