Social media use among adolescents continues to increase each year. This cross-sectional study explored how the amount of time spent using social media and the frequency of specific behaviors on social media, namely, behaviors that involve self-objectification, were related to body surveillance and body shame among a sample of early adolescents (N = 142; 43 boys and 99 girls, [X-bar][subscript age] = 12.44 years, SD[subscript age] = 0.61). Utilizing self-report measures, three types of social media were examined: Twitter, Facebook, and Instagram. Analyses indicated that greater levels of self-objectifying social media use predicted greater body shame among youth, and this was mediated by an associated increase in body surveillance. This mediation was moderated by self-monitoring and gender, such that the mediating role of body surveillance was stronger among girls and adolescents who are particularly focused on others for approval (i.e., high in self-monitoring). Implications of these findings are discussed.