When young adult women and men are exposed to idealized images in traditional media outlets, they often experience body dissatisfaction. As the use of social media increases, so do the opportunities for appearance-based comparisons. Individuals who are heavy users of social networking sites also tend to exhibit body dissatisfaction. Body appreciation is a personal characteristic that seems to counteract the negative influence traditional media exposure, and it may have a similar effect for social media exposure. The purpose of our research was to investigate the impact of body appreciation on the relationship between social network sites usage and body dissatisfaction with young adult women and men. An online survey method was employed to collect the data. Participants, who were recruited using Amazon Mechanical Turk, completed a questionnaire featuring previously developed scales. The multi-item scales featured seven-point, Likert-type items. The data were analyzed using the two-step approach to structural equation modeling. The structural model was used to test the hypotheses. All of the hypotheses were supported. Social networking sites usage was positively related to body dissatisfaction. Fortunately, though, body appreciation did reduce body dissatisfaction as a moderating variable. Because usage of social networking sites is ubiquitous in today’s society, understanding the impact that these sites have on users is important. Our findings indicate that negative outcomes, such as body dissatisfaction, can occur as a result of social networking sites usage. Uncovering ways to limit these negative outcomes, including increasing body appreciation, is vital for young adults’ mental health.