This study aims to quantitatively assess the resilience of 229 local governments in South Korea against heatwaves using the Relative Disaster Resilience Framework (Zobel et al., 2021). This method is an extension of the Resilience Triangle Theory that incorporates both loss magnitude and recovery time. The framework allows flexible and objective evaluation by employing resilience thresholds of zero cases of heat illness and average electricity consumption during the milder spring and autumn seasons. Physical resilience was assessed using the number of cases of heat illness, while socioeconomic resilience was evaluated through summer electricity usage. Results showed that socioeconomic resilience was generally higher than physical resilience, indicating that energy systems recover more effectively than public health systems during heatwave events. Latent profile analysis revealed three distinct regional groups: Group 1 (43.7%) with high physical and socioeconomic resilience, Group 2 (50.7%) with low physical but high socioeconomic resilience, and Group 3 (5.7%) with high physical but low socioeconomic resilience. These groupings provide critical insights into differentiated policy responses. Group 2 regions require improved access to emergency medical services and heatwave shelters, while Group 3 regions might benefit from enhanced energy efficiency programs and demand-side energy management. By combining quantitative metrics with a flexible theoretical framework, this study offers a replicable method for evaluating urban resilience to heatwaves. The findings can inform evidence-based policymaking and support the development of tailored local adaptation strategies in response to increasing climate-related risks.