Social media has become increasingly widespread among young adults, yet its relationship to depression and anxiety may depend on the users' experiences. For LGB+ individuals, who exhibit disproportionate rates of anxiety and depression, social media may present a unique source of acceptance or of hostility and stress. This study examined whether sexual orientation (SO) moderated the relationship between social media experiences of acceptance of acceptance and hostility and symptoms of depression and anxiety. Questionnaires assessing depression, anxiety, and social media experiences were completed by 382 young adults from a large Midwestern university at three time points. Significant interactions were observed between SO and social media experiences of acceptance on depression from T1 to T2 and T1 to T3. Similar results were found for anxiety from T1 to T2. Higher levels of acceptance on social media predicted lower symptoms of depression and anxiety in LGB+, but not heterosexual, participants. No significant interactions were observed between SO and social media experiences of hostility on depression or anxiety. Social media may serve as an important should of support and acceptance, rather than a source of hostility, that can protect against depression and anxiety in LGB+ individuals. [ABSTRACT FROM AUTHOR]