Although peer support in response to online disclosures of suicidality may be imperative for suicide prevention efforts, little is known as to how often support is provided or what predicts giving support. This study addresses this issue by investigating the odds of providing peer support in response to simulated online disclosures of suicidality. While interacting with a simulated Facebook newsfeed, participants (N = 690, Mage = 20.24, 527 female) were given the opportunity to leave comments on two posts disclosing low, moderate, or severe risk for suicide. Participants also completed questionnaires on their symptoms of depression and anxiety, experience with a loved one's suicidality, and Facebook use strategies. Only 33.6% of participants left a positive, supportive comment on at least one of the two suicide posts. Content severity, experience with a loved one's suicide attempts, and use of Facebook to meet people were predictive of providing positive comments. These findings suggest that young adults vary in their propensity to provide support after encountering a suicide disclosure online and that giving support is driven by a combination of contextual and intrapersonal factors.