Glacial Lake Outburst Floods (GLOFs) pose a significant and growing threat to the Hindu Kush Himalaya (HKH) region, which is home to over 270 million people and provides lifelines to 2.1 billion people downstream. Accelerated glacier retreat due to rising temperatures has contributed to the rapid formation and expansion of glacial lakes. Adopting a transdisciplinary science-policy perspective, this study examines GLOF risks alongside response strategies adopted by HKH countries and the available international assistance supporting their implementation to identify critical adaptation gaps. It further proposes strategies to bridge GLOF adaptation gaps and strengthen adaptation governance in the region. An analysis of 493 historical GLOF events from 1533 to 2024 highlights increasing risks exacerbated by climate change. Additionally, a review of national adaptation planning instruments submitted by the HKH governments—including National Adaptation Plans (NAPs), Nationally Determined Contributions (NDCs), and National Communications (NCs)—reveals significant shortcomings in recognizing GLOF-specific adaptation needs, long-term adaptation strategies, and transboundary collaboration. Despite the escalating threat, funding for GLOF-specific projects under major post-2015 climate finance mechanisms remains limited, exposing critical gaps in adaptation finance, technology, and institutional capacity. This study underscores the urgent need to integrate GLOF risks into governments’ adaptation policies and plans, enhance regional cooperation, and ensure sustainable financial, technical, and institutional support. Our findings emphasize the importance of strengthening early warning systems, establishing robust monitoring mechanisms, fostering community resilience, and promoting transboundary adaptation initiatives to mitigate future risks and support climate-resilient development in the HKH region.