Since social networks have become an essential part of young people’s lives, the present study examined the relationship between sharing and manipulating selfies on Instagram and related outcomes on body image. A total of 350 young adults from Italy and Portugal participated in the study. They completed measures on selfie-sharing, selfie-manipulation, appearance-based comparison, internalization of beauty ideals, and shame for their bodies. Gender, nationality, and type of account (public/private) were hypothesized to moderate the examined relationships. The results partially confirmed the hypothesized model, indicating that sharing selfies was positively associated with body shame through appearance-based comparison, which was also positively associated with beauty-ideal internalization. In contrast with the hypotheses, selfie manipulation was negatively associated with body shame. Gender and type of social networks account moderated these relationships, whereas no moderation role was found with regard to nationality. Findings showed that there are specific behaviors on Instagram associated with the feeling of shame about one’s own body. Limitations of the present study and implications for future research are discussed from a sociocultural perspective.