The widespread use of the Internet and the popularity of mobile devices have greatly changed our communication habits. Due to their popularity, social networking sites (SNS) are at the center of online relationships, including romantic ones. This paper explores the emerging role of SNS on relationship social comparison (RSC) and individual and relational predictors of RSC. The present study used an experimental design to evaluate the role of relational posts of others' on SNS. Specifically, RSC based on posts by others on SNS were analyzed. In addition, possible other factors that influence the tendency to make RSC, namely relationship satisfaction, investment, quality of alternatives, and adult attachment orientation were examined. The sample of the study consist of 251 participants. 180 (71%) were females and 71 (29%) were males. The sample's mean age was 28.16 (SD=6.32). According to the results, there was no significant effect of exposure to relational posts on RSC. On the other hand, the results showed that anxious attachment style and investment in romantic relationships positively predicted RSC tendency. On the contrary, relationship satisfaction negatively predicted RSC tendencies. This study provided an important insight for understanding the effects of SNS on RSC in terms of individual and relational factors.