Groundwater, as a vital freshwater source in arid regions, faces significant risks of contamination from various natural and anthropogenic sources such as agricultural and industrial activities, sewage ponds, open drains, and saltwater intrusion. This chapter provides a comprehensive review of the contamination sources affecting groundwater aquifers in arid regions and explores diverse protection techniques employed to safeguard groundwater quality. The review encompasses an assessment of different investigative methods used to understand aquifer contamination, including geophysical, hydro-geochemical, experimental, and mathematical approaches. Furthermore, the study highlights proven methods for effectively protecting groundwater in arid regions, such as aquifer operation, hydraulic barriers, material management, and physical barrier management. By comprehending the sources and protection techniques associated with groundwater contamination, we can implement effective measures to prevent contamination and ensure the availability of clean groundwater for future generations. Thus, the future application of these protection methods holds immense promise in ensuring the availability of pristine freshwater and safeguarding human health, particularly in regions facing high water stress such as Egypt, and the adverse effects of climate change, notably arid and semi-arid regions. By adopting and integrating these approaches, water resources management can significantly address the challenges posed by groundwater pollution and secure sustainable water supplies. This chapter serves as a valuable resource for researchers and practitioners involved in the management and conservation of groundwater resources.