Maintaining the health of biodiversity and ecosystem services is becoming an increasingly important concern for the global community. The biodiversity-rich Hindu Kush Himalayan (HKH) region provides a myriad of ecosystem services but is experiencing rapid biodiversity loss and habitat degradation under the influence of climate change and other drivers of change. Biodiversity and ecosystem services often transcend geopolitical boundaries, and biodiversity management requires efforts that span larger landscapes. Globally, a landscape approach to management is recognized for its ability to reconcile objectives of biodiversity conservation and sustainable development. In order to institutionalize the landscape approach to enhance ecological integrity and sociocultural resilience in the region, the International Centre for Integrated Mountain Development, with its partners in 8 countries, pioneered transboundary landscape (TBL) conservation and development initiatives between 2007 and 2019. This article reviews processes, outputs, and outcomes of the 4 TBLs designated and operationalized in the HKH region and distills key learning from an in-depth external evaluation of the Kailash Sacred Landscape initiative. The article draws the inference that transboundary cooperation as a collaborative process is both dynamic and evolutionary. Evidence, collaborations, inclusive partnerships, ownership, cross-border learning, joint policy influencing, and systemic thinking are key ingredients for any transboundary cooperation. TBLs have the potential to galvanize regional cooperation processes that help individual countries collectively address biodiversity conservation and development-related milestones, targets, and impacts.