Urban flood risk management (FRM) increasingly relies on Nature-based Solutions (NbS), but their ability to provide social and ecological co-benefits remains unclear. This study proposes a coupled social-ecological framework to explore NbS for FRM, revealing that ecological measures are unevenly distributed globally, with some solely targeting flood mitigation potentially causing unintended negative consequences for society and ecosystems. NbS-FRM has the potential to provide both social and ecological co-benefits, but gaps remain in resilience thinking, environmental change consideration, and collaborative efforts. The framework highlights the need to balance NbS interventions to achieve equitable and sustainable FRM with improved human well-being and ecosystem health. Floods are a severe climate-related disaster, with projected increases in flood frequency by 2050. Urban areas face heightened impacts due to population growth and increased exposure to flooding, which disrupts hydrological processes and affects flood mitigation. Flood risk involves hazard, exposure, and vulnerability. Green and blue spaces are used in urban FRM, but measures targeting only flood mitigation may have unintended consequences. NbS can mitigate flood hazards and enhance biodiversity, addressing climate, societal, and biodiversity challenges. The application of NbS determines whether multiple benefits can be achieved. For example, mangrove restoration reduces coastal protection costs and limits ecosystem loss; floodplain vegetation increases biodiversity and buffers riverine overflow; rain gardens and green roofs reduce stormwater runoff and thermal exposure. However, NbS use in urban FRM has not yet achieved dual social and ecological co-benefits, with issues including inadequate stakeholder involvement and uneven distribution of benefits. Cities are complex social-ecological systems (SESs) with intense interactions between society and ecosystems. Coupled SES frameworks can foster resilience thinking and address challenges in NbS planning and implementation. However, NbS use for urban flood regulation has not yet achieved dual social and ecological co-benefits. A general SES framework, as proposed by Ostrom (2009), facilitates multidisciplinary efforts to understand SES interactions. Extending this framework to NbS research and practice is essential to couple social and ecological perspectives in urban FRM. The study identifies key research trends and gaps in NbS-related ecological measures for urban FRM. It highlights the need for further research to address flood-vulnerable regions in the Global South and to incentivize nature-based projects. Ecological measures are unevenly distributed globally, with more studies in the Global North. Restoration, engineered, and hybrid measures are biased in the reviewed studies, with hybrid measures being more common. Ecological measures may have unintended effects on ecosystems and society, such as water eutrophication and mosquito prevalence. NbS can provide co-benefits for both people and nature, but challenges remain in balancing social and ecological outcomes. The study emphasizes the need for resilience thinking, process-based effectiveness evaluation, and collaborative approaches to monitor and manage NbS. Future research should focus on the resilience of NbS underUrban flood risk management (FRM) increasingly relies on Nature-based Solutions (NbS), but their ability to provide social and ecological co-benefits remains unclear. This study proposes a coupled social-ecological framework to explore NbS for FRM, revealing that ecological measures are unevenly distributed globally, with some solely targeting flood mitigation potentially causing unintended negative consequences for society and ecosystems. NbS-FRM has the potential to provide both social and ecological co-benefits, but gaps remain in resilience thinking, environmental change consideration, and collaborative efforts. The framework highlights the need to balance NbS interventions to achieve equitable and sustainable FRM with improved human well-being and ecosystem health. Floods are a severe climate-related disaster, with projected increases in flood frequency by 2050. Urban areas face heightened impacts due to population growth and increased exposure to flooding, which disrupts hydrological processes and affects flood mitigation. Flood risk involves hazard, exposure, and vulnerability. Green and blue spaces are used in urban FRM, but measures targeting only flood mitigation may have unintended consequences. NbS can mitigate flood hazards and enhance biodiversity, addressing climate, societal, and biodiversity challenges. The application of NbS determines whether multiple benefits can be achieved. For example, mangrove restoration reduces coastal protection costs and limits ecosystem loss; floodplain vegetation increases biodiversity and buffers riverine overflow; rain gardens and green roofs reduce stormwater runoff and thermal exposure. However, NbS use in urban FRM has not yet achieved dual social and ecological co-benefits, with issues including inadequate stakeholder involvement and uneven distribution of benefits. Cities are complex social-ecological systems (SESs) with intense interactions between society and ecosystems. Coupled SES frameworks can foster resilience thinking and address challenges in NbS planning and implementation. However, NbS use for urban flood regulation has not yet achieved dual social and ecological co-benefits. A general SES framework, as proposed by Ostrom (2009), facilitates multidisciplinary efforts to understand SES interactions. Extending this framework to NbS research and practice is essential to couple social and ecological perspectives in urban FRM. The study identifies key research trends and gaps in NbS-related ecological measures for urban FRM. It highlights the need for further research to address flood-vulnerable regions in the Global South and to incentivize nature-based projects. Ecological measures are unevenly distributed globally, with more studies in the Global North. Restoration, engineered, and hybrid measures are biased in the reviewed studies, with hybrid measures being more common. Ecological measures may have unintended effects on ecosystems and society, such as water eutrophication and mosquito prevalence. NbS can provide co-benefits for both people and nature, but challenges remain in balancing social and ecological outcomes. The study emphasizes the need for resilience thinking, process-based effectiveness evaluation, and collaborative approaches to monitor and manage NbS. Future research should focus on the resilience of NbS under