Gaia, also spelled as "Gaea", "Gaïa", or "Ge", can refer to any one of the following:

• Gaia is a Greek and Roman goddess, also known as the Earth Mother.

• Gaia theory is a group of scientific theories about how life on Earth may regulate the planet's biosphere to make it more hospitable to life. This article discusses all scientific views on the subject in general, including the views of Drs. James Lovelock, Lynn Margulis, Richard Dawkins, Carl Sagan, etc.

• Gaia philosophy is a set of varied philosophical views related to the Gaia theory.

• GAIA is the acronym for the Grantley Adams International Airport located in Barbados.

• Gaia is the name of a space astronomy mission, due for launch in 2011 by the European Space Agency.

• Gaea is a crater on Amalthea (Jupiter's third moon). It is 80 kilometers across and approximately 16 kilometers deep.

• Gaia is a fictional planet set in Isaac Asimov's Foundation Series. It is society in which all animals, plants, and even inanimate matter are telepathically connected, forming a single sentient planet-wide entity.

• Gaia is the name of a chess engine.

• Several music albums are titled Gaia:
  • Gaia (Olivia Newton-John, 1994)
  • Gaia (Mägo de Oz, 2003)

• Gaia is a fictional alien mutant in the Marvel comics universe.

• Vila Nova de Gaia (Gaia new town) is a city in Portugal.

• GAIA is the acronym of "Global Alternate Information Applications," an Indian organisation working in media with alternative content.

• Gaia is the short name for the popular Internet forum Gaia Online.

• Gaea is the name of the fictional planet where the animé The Vision of Escaflowne takes place.