Large-scale crises often prompt the centralisation of state power due to the need for swift responses and coordination challenges. However, advocates of decentralised crisis management contend that polycentric institutions allow for more adaptive responses. This chapter explores Ukraine’s decentralised response to the 2022 Russian full-scale invasion at the local level, based on mixed-methods research conducted with Ukrainian local self-government authorities from 2022 to 2023. Findings reveal that local governments utilised fiscal and political autonomy gained from decentralisation reforms to bolster wartime resilience. Drawing on literature concerning polycentricity and collaborative governance, the chapter theorises three key mechanisms for decentralised crisis response: knowledge facilitation, resource mobilisation, and innovation. These insights underscore how decentralised systems can effectively tackle crises, providing lessons for democratic states beyond Ukraine.