Groundwater–surface water (GW-SW) interactions are essential for understanding the physical, chemical, and biological attributes of both sub-surface and surface ecosystems, as well as the functioning of riparian ecosystems. The interaction between GW-SW involves the exchange of water and chemicals between the land surface and the sub-surface. This interaction plays a crucial role in Integrated Watershed Studies, where methods such as field/experimental, analytical modeling, numerical modeling, and semi-analytical methods are used to analyze and predict GW-SW water interactions. Understanding these interactions is essential for managing water resources effectively and addressing issues like flooding and water scarcity. Factors such as hydrological conditions, geological structure, water–rock interaction, climate, land use, and the presence of substances like nutrients and toxic substances influence the interactions between GW-SW. Various methods, including field/experimental, analytical modeling, numerical modeling, and semi-analytical methods, are employed to study these interactions and assess their impact on water resources. These interactions play a crucial role in sustainable river basin management and environmental sustainability. In this chapter, we explore the definition and importance of GW-SW management. This chapter focuses on the methods measuring and modeling their interaction and the hydrological management techniques to optimize GW-SW interactions. Also, in this chapter, the capability of remote sensing in the management of GW-SW and their interaction, the impact of climate change on the interaction of GW-SW, and their management have been described.