With the visual turn in online communication, selfies have become common on social media. Although selfies as a way of self-representation provide people with more chances to express themselves, the adverse effects selfies could bring to users' body image need to be treated seriously. This study tested whether selfie-viewing behaviour on social media was related to facial dissatisfaction and whether appearance comparisons played a mediating role. Moreover, the self-objectification was examined as a moderator between selfie-viewing behaviour and facial dissatisfaction via appearance comparisons. Results showed that more selfie-viewing was associated with higher facial dissatisfaction, and this relationship was mediated by appearance comparisons. The study also found that self-objectification moderated the indirect relation between selfie-viewing and facial dissatisfaction via appearance comparisons. Gender differences were also found to affect the mediation model. Our research provides new insights into the interactions between social media use and perception of body image.