Groundwater is the major source of water supply in many countries across the world. Despite huge significance, groundwater resource is heading for a crisis across the world, particularly in densely populated countries due to rapid expansion of groundwater-based irrigated agriculture and inappropriate irrigation practices. Recent studies suggest that climate change will pose another major threat to groundwater resources in the near future. Direct and indirect impacts of climate change on groundwater resources and possible adaptation measures that can be adopted to mitigate the negative impacts of climate change are broadly discussed in this chapter. The case studies presented in this chapter suggest that climate change will affect groundwater recharge, discharge, storage, saltwater intrusion, biogeochemical reactions, chemical fate and transport, etc. However, groundwater will be affected less directly and more slowly compared to surface water bodies. The effect of climate change on groundwater resources will also vary widely for different climatic regions. However, the quantification of the impacts is still very difficult due to uncertainty in climate projections and the response of the hydrological system to climate variability. The major focus of adaptation and mitigative measures should be given to the groundwater recharge zone to protect this precious resource from the adverse effect of climate change. It is expected that this chapter will help a broad range of readers to improve their understanding of climate change impacts on groundwater resources.