The Galaxy Alliance was an alliance of planets which existed in the universe of the Voltron Lion Force, a dimension separate from the universe of Robotechnology. It included the Voltron Universe version of Earth and Arus, and was founded on Earth.
Some of the early founders of the alliance included the Voltron Universe's versions of Donald Hayes, Rolf Emerson, T. R. Edwards, Roy Fokker, and Anatole Leonard.
Long after the founding of the alliance, the Voltron Lion Force was under the command of the alliance in the war against the Drule Empire. (Robotech/Voltron: 1, 3)