The Galactic Commons is a large and powerful multi-species alliance. Founded by the Aeluon, Harmagian and Aandrisk species, it has since expanded to include many more.

Originally, the treaty was established to bring an end to hostilities between the Harmagian and the Aeluon. They came to a mutually beneficial agreement, with the Harmagian providing wealth and the Aeluon providing firepower, while the Aandrisk were the diplomats who brokered the peace.

Other species present in the Galactic Commons are Humans, Laru, and the Quelin.

It is portrayed in the books as a sort of "European Union" of space - beaurocratic, usually well meaning and sometimes a plain hassle because of the legislation they enact or the descisions they make.

They have various authorities, including the GC transport board which deals with Deepods and subspace tunneling affairs.