Despite considerable public and scholarly debate about the role of social media in self-injurious thoughts and behaviors (SITBs), no comprehensive, quantitative synthesis of this literature has previously been undertaken. The current systematic review and meta-analysis examines associations between social media use and SITBs, including suicidal ideation, suicide plans, suicide attempts, and nonsuicidal self-injury (NSSI). A range of social media behaviors and experiences were identified, including cybervictimization and perpetration, exposure to and generation of SITB-related content, problematic or addictive use, sexting, social media importance, and frequency of use. A systematic search of PsycINFO, Medline, CINAHL, and the references of prior reviews yielded 61 eligible studies. Results largely suggested medium effect sizes for associations between the social media constructs and SITBs examined. The majority of studies identified focused on cybervictimization, and results suggested stronger positive associations between cybervictimization and suicidal ideation and attempts for adolescents compared to adults. No evidence emerged for associations between frequency of social media use and SITBs; however, studies on this topic were limited. Overall, findings highlight the utility of examining specific social media behaviors and experiences, and point to the need for more research in this area.