We explored how, and to what extent, social media exposure to body image content affected the obesity stigma, in relation to adolescents' internal and external attributions. Participants were 202 high school students in South Korea who completed an online survey. The results confirmed the main effect of internal attributions in which those adolescents who blamed individuals for being obese demonstrated high levels of obesity stigma, indicating a need to communicate with adolescents regarding the causes of being overweight or obese. No main effects of external attributions and social media exposure were found. However, the interaction effect between external attributions and social media exposure was significant. This means that body image content emphasizing thinness and physical attractiveness on social media may have strengthened the obesity stigmatization through external attributions. The results of this study offer a useful direction for addressing the obesity stigma for adolescents in the rapidly evolving communication landscape.