Geothermal desalination refers to the process of using geothermal energy to power the process of converting salt water to fresh water. The process is considered economically efficient, and while overall environmental impact is uncertain, it has potential to be more environmentally friendly compared to conventional desalination options. Geothermal desalination plants have already been successful in various regions, and there is potential for further development to allow the process to be used in an increased number of water scarce regions.

Desalination is a process that takes away mineral components from saline water. More generally, desalination is the removal of salts and minerals from a target substance, as in soil desalination, which is an issue for agriculture. Saltwater is desalinated to produce water suitable for human consumption or irrigation. The by-product of the desalination process is brine. Desalination is used on many seagoing ships and submarines. Most of the modern interest in desalination is focused on cost-effective provision of fresh water for human use. Along with recycled wastewater, it is one of the few rainfall-independent water resources.