Geothermal is related to energy and may refer to:

• Geothermal (geology), heat that comes from within the Earth
• Direct exchange geothermal heat pump, a method of heating and cooling with the energy of the earth using direct exchange of heat
• Geothermal desalination, the production of fresh water using heat energy extracted from underground rocks
• Geothermal heating, a method of heating and cooling a building using underground heat
• Geothermal power, electricity generated from naturally occurring geological heat sources
• Hot dry rock geothermal energy, Heating water in hot deep rock
• Geothermal heat pump, a method of heating and cooling using a heat pump with the earth as a heat reservoir
• Earth sheltering, constructing a building into a hill side or Earth berm to reduce heating and cooling requirements
• Earth cooling tubes, using ambient Earth temperature to cool and dehumidify air