Background <p>Mood disorders and related suicidal ideation among adolescents are pressing global health concerns. Although negative life events (NLEs) are recognized risk factors, the psychological mechanisms underlying the transition from adversity to suicidal ideation (SI), particularly in clinically depressed adolescents, remain unclear. This study is grounded in the vulnerability‒stress framework and investigates the developmental and psychological pathways linking NLEs and suicidal ideation in a clinical sample of depressed adolescents.</p> Methods <p>A total of 341 adolescents (aged 10–19) with clinically diagnosed depression were recruited from five psychiatric hospitals in China via a multicenter design. The participants completed self-report questionnaires assessing NLEs, resilience, and suicidal ideation. A moderated chain mediation model was used to test whether resilience and depressive symptoms sequentially mediate the relationship between NLEs and SI and whether age moderates this pathway.</p> Results <p>NLEs were associated with lower resilience, which predicted greater depressive symptoms and ultimately higher SI. Furthermore, age significantly moderated the relationship between depressive symptoms and SI. Simple slope analysis confirmed that depressive symptoms had a stronger predictive effect on SI in younger adolescents.</p> Conclusion <p>Our findings reveal a critical chain of vulnerability: negative life events were associated with lower resilience and higher depressive symptoms, which in turn predicted suicidal ideation. The significant moderating role of age suggests that this pathway is sensitive to development and is especially potent in younger adolescents. This multicenter study provides compelling evidence of the importance of fostering resilience and treating depressive symptoms as key targets in suicide prevention efforts, especially through interventions tailored to different age groups.</p> Clinical trial number <p>Not applicable.</p>