Groundwater is the main source of drinking water as well as agricultural and industrial usage. Unfortunately, groundwater quality has been degraded due to improper waste disposal practices and accidental spillage of hazardous chemicals. Therefore, it is critical that the groundwater contamination be prevented and the contaminated groundwater at numerous sites worldwide be remediated in order to protect public health and the environment. This chapter provides an overview of relevant regulations, general remedial approach, and most commonly used physical and chemical groundwater remediation technologies. The remediation technologies include pump-and-treat, in-situ air sparging, in-situ flushing, and permeable reactive barriers. The process description, applicability, limitations and a case study for each of these technologies are also presented.