Despite the widespread use of social networking sites (SNS) such as Facebook, an adequate understanding of their impact on the users’ mental health is still lacking. The present study intends to expand on the current understanding of the linkage between social networking site use and mental health. Our study explored how Facebook use may be associated with obsessive-compulsive disorder (OCD), with the inclusion of obsessive-compulsive beliefs as a mediator. One hundred and fifty-six undergraduate students completed the questionnaire given. Overall, Facebook use contributed to OCD severity through obsessive-compulsive beliefs as the mediator. The present study also yielded other relevant results for cyberpsychology that may help pave the way for future studies. © 2007-2015 Cyberpsychology.