Gallia (Japanese: ガリア Garia), or the Kingdom of Gallia, is a kingdom in Halkeginia, located to the southeast of Tristain. Germania is on its eastern border, in the Alden Forest. It is the most populous country in Halkegnia, with a population of more than 15 million citizens. It is also the second largest country in Halkeginia, and it most similar to France, although it also seems to occupy where Iberia should be as well.

Within the Gallian royal family, murders and assassination attempts have led to an unstable royalty. In addition, there's a law that states if twins are born in the royal family one of the twins must die to prevent power struggles for the throne.This is reflected on Gallia's crest of "Two staves, one crown".

Gallia is the only nation mentioned so far that has "black ops" organizations in their service, and regularly hires mercenaries to do jobs.

The royal capital is called Lutèce, but the royale palace is in Versailles. There is a city named La Rochelle in the mountains, which is also a major treeport.