© 2021 Termedia Publishing House Ltd. All rights reserved.Background: Social media addiction (SM) is a widespread and severe problem in today's world. It is associated with both selfesteem (SE) and general belongingness (GB). There are many studies related to these associations in the literature, but in this research an attempt was made to explain this mechanism based on social comparison theory. The aim of this study is to examine the indirect effect of social comparison (SC) on the relationship among SM, SE, and GB. Participants and Procedure: The sample consisted of 311 university students studying at a state university in Turkey. Data were gathered by using a demographic information form, the Rosenberg Self- Esteem Scale, the General Belongingness Scale, the Social Comparison Scale, and the Social Media Addiction Scale- Student Form. The mediator effect of SC was determined via structural equation modelling. Results: The results indicate that SC has an indirect effect on the relation between SM and SE. Similarly, SC has an indirect effect on the relation between SM and GB. Conclusions: People tend to compare themselves with other individuals, and this SC process can be made very easily and quickly via social media tools. Moreover, social media sites offer plenty of opportunities for SC, and this comparison consists of sometimes upward SC and sometimes downward SC processes. Downward and upward SC processes can regulate individuals' emotions, SE, and GB levels in social media either in a negative or positive way. The mediating role of SC in the relationship between SM, SE, and GB can be examined in terms of these upward and downward SC processes.