The United Federation of Planets is the government for the Humans and ther species.
- Humans: Originating from Earth, Humans are the most numerous in Star Fleet, and in many ways the most aggressive, militarily and economically. Much of the internal stress within the Federation is from the other races trying not to be overwhelmed by the Humans.
- Vulcans: Guided by Logic, the Vulcans are one of the oldest spacefaring races in the known Galaxy.
- Alpha-Centaurans: Native to Alpha-Centaurai (known to them as Culden-Feyr), the ACs are a matriarchal society, born of a time when warfare had devastated the male population. While there are no laws or such restricting male activity, few join Star Fleet. Alpha-Centaurns are biologically so close to human that they may interbreed and has led to speculation of 'seeding.'
- Rigellians: Blue with while highlights skinned natives of Rigel, they were appalled that some races outside the Federation were still conquering, rather than working with, weaker powers. As a result, while the Humans may have the highest number in Star Fleet, the Rigellians have the highest percentage of their overall population serving.
- Andorians: Perceived as humorless and easily irritable, the blue skinned, antennaed natives of Andoria were one of the last to give up their separate fleet.
- Cygnans: Former Kzinti subjects, the people of Cygnus became part of the Federation with the declaration of the border in Y102. A major reason for the Second Federation-Kzinti War was their desire to regain Cygnus and its technological gifted population. Cygnus became a Full Member during the War. The Cygnan gift with technology is attributed to the visit of the Sky Fathers in their ancient history. As a result, the Cygnans are the most likely to violate the Prime Directive as they seek to spread this gift.
- Tellarites: Hairy Pignosed people with a talent for engineering and habit of argument.
- Brecons: Tall, four-armed, golden-skinned humanoids best known for the fact that they work in Star Fleet and other major operations in pairs, one from each to two old rival factions.
- Prellarians: Dwarflike humanoids from a high gravity world. Best known for their artificial gravity work, and their notable fear of heights.
- Mynieni: Small, non-human-like creatures, the Mynieni had little to do with the Federation government until they suddenly began to join en-masse.
- Deians: Blue skinned, but nearly human, this race is known for the immense beauty of its individuals, a factor that belies their skills.
- Arcturians: Elf-like humanoids with a skill for hand-to-hand combat.