Flooding poses a significant environmental challenge, particularly in tropical river basins where intense rainfall and complex hydrological dynamics frequently cause severe inundation. Southeast Asia, characterized by high annual rainfall and rapid urbanization, faces heightened flood risks exacerbated by climate change. Increased frequency and intensity of flood events in Kota Tinggi, Malaysia, necessitate effective strategies to improve flood resilience. Nature-based solutions (NbS) are emerging as a promising approach for sustainable flood adaptation and mitigation. This study evaluates the effectiveness of NbS in mitigating flood risks in Southeast Asia, focusing on tropical river basins. The case of Kota Tinggi in Johor, Malaysia, serves as a focal point for examining the practical application and challenges of NbS. Utilizing a comprehensive literature review and Multi-Criteria Decision Analysis (MCDA), the research assesses the relative effectiveness of different NbS, considering factors such as flood reduction capacity, environmental benefits and socio-economic impacts. Each criterion was assigned a weight based on its relative importance through a comprehensive literature review and each NbS option was scored based on its performance in each criterion. The MCDA results indicate that reforestation is the most suitable NbS for flood mitigation in the region. The findings underscore the importance of integrating NbS into regional flood management strategies to enhance resilience against increasing flood hazards. The outcomes are expected to inform policymakers, practitioners and researchers on the benefits and limitations of NbS, highlighting the importance of integrating natural and engineered approaches to address the growing flood risks in the region.