The Earth Alliance was the name of the military alliance consisting of United Earth and its allies who fought against the Romulan Star Empire during the Earth-Romulan War in the 2150s. (ST - Destiny novel: Mere Mortals)

The Earth Alliance's relationship with the Coalition of Planets – including whether or not "Earth Alliance" was just an informal name for the Coalition – has yet to be established.

"The Earth Alliance" was also the name of Earth's world government in the 1990s science fiction television series Babylon 5.