Urban agglomerations are seen as a new spatial pattern to address the problems encountered in urban development, with significant practical implications for enhancing the carrying capacity, adaptability to external environmental changes, and disaster resistance of urban systems. However, there is a scarcity of literature investigating the impact of urban agglomeration development on urban resilience. Exploiting the quasi-natural experiment of urban agglomeration plans in China, this study investigates the impact of regional integration policies (RIPs) on urban resilience across four dimensions: economic, social, ecological, and infrastructure. Our results indicate that: (1) RIPs have significantly improved urban resilience by 8.6%, as verified by various tests. (2) RIPs can improve economic resilience remarkably without any obvious effect on social and infrastructure resilience and even have a negative affect on ecological resilience. (3) Mechanism analysis indicates that RIPs enhance urban resilience by accelerating diversified agglomeration and specialized agglomeration, as well as promoting urban innovation. (4) Heterogeneity analysis shows that the policy-driven effect is more pronounced in core cities, non-resource-based cities, and cities with a high level of innovation. The aforementioned findings hold valuable implications in promoting simultaneous enhancement of urban agglomerations and urban resilience.