BACKGROUND: Insomnia has been identified as a potential risk factor for suicidality. However, to date, few studies using the longitudinal-design have examined the underlying mechanism of this relationship. Based on a resilience perspective, this study aimed to investigate the dynamic longitudinal relationships between insomnia, resilience, and suicidality. METHODS: A total of 5785 freshmen were sampled from a large-scale health-related cohort among Chinese college students. This study spanned six waves, covering the period from 2020 to 2022. Data from T to T were used because resilience was not measured at baseline (T) and T. The cross-lagged panel models and the latent growth curve mediation model were used to examine the longitudinal dynamic relationships between insomnia, resilience, and suicidality. RESULTS: The results showed that insomnia symptoms and suicidality mutually predicted each other, and resilience played a longitudinal mediating role in linking insomnia symptoms and suicidality. CONCLUSIONS: Given that resilience served as a mediator in the relation between insomnia symptoms and suicidality, some resilience-oriented prevention and intervention programs will be helpful in reducing the risk of suicide among university students.