Eleven studies ( = 2,254; 2 preregistered) examined whether ostracism would trigger suicidal thoughts and whether perceived meaning in life would account for this effect. The feeling of ostracism was induced via recalling a past experience (Studies 1a, 1c, 2c, and 3b), imagining a future experience (Studies 1d, 1e, and 2b), engaging in an online real-time interaction (Studies 1b and 2d), or receiving bogus personality feedback (Study 3a). Across all 11 studies, ostracism increased suicidal thoughts. Study 1a found that ostracism increased implicit associations of "death" and "me" relative to "life" and "me" on the Implicit Association Test of Suicide (Nock et al., 2010). In Study 1b, ostracized participants showed more suicidal thoughts in imagined stressful situations than did included participants. Studies 1c, 1d, and 1e further showed that ostracism increased explicit suicidal thoughts compared with both inclusion and neutral experiences. Furthermore, we found that perceived meaning in life accounted for ostracism's effect on suicidal thoughts (Studies 2a and 2b), even after controlling for depressive affect (Study 2c). In Study 2d, a preregistered study, we directly compared the contributions of perceived meaning in life and the 4 basic needs and mood proposed in William's (2007, 2009) ostracism framework, and we found that perceived meaning in life had a distinct mediating role in the ostracism-suicidal thinking link. Finally, Studies 3a and 3b found that self-affirmation exercises reduced suicidal thoughts following ostracism. Life lacks meaning without social connection, thereby activating suicidal thoughts. (PsycInfo Database Record (c) 2021 APA, all rights reserved).