The chapter provides a comprehensive overview of the intricate relationship between land and water resources in one of the most densely populated and ecologically diverse regions of the world. South Asia, comprising countries like India, Pakistan, Bangladesh, Nepal, Bhutan, and Sri Lanka, faces unique challenges and opportunities due to its complex geography and climatic conditions. This introduction elucidates how land use and water availability are interlinked, affecting agricultural practices, urban development, and ecological balance. The chapter begins by outlining the conceptual and theoretical framework of the Land and Water Nexus and then the historical and contemporary significance of land and water resources in South Asia. It examines the impact of rapid population growth, industrialization, and climate change on these critical resources. The interplay between land use changes—such as deforestation, urban expansion, and agricultural intensification—and water resource management is highlighted, showing how alterations in land cover can influence water availability and quality. The chapter explores the socioeconomic dimensions of the land–water nexus, emphasizing how disparities in resource access can lead to conflicts and affect livelihoods. It sets the stage for subsequent discussions on policy interventions, sustainable practices, and the need for collaborative approaches to address the pressing issues of resource management in the region.