* Terrans. Referred to as "Commons" in the Japanese version, this is what many space creatures call humans.
* Ctarl-Ctarl. A cat-like alien race. The Ctarl-Ctarl have superior senses of hearing, smell and sight and vast strength as well as an ability to turn into large, feral beasts completely at the mercy of their instincts (usually resembling huge felines and perhaps Lupines or Vulpines). The Ctarl-Ctarl are a vast empire that, after many battles with Terrans, have established trade treaties and are now on neutral terms. The Frontier - the area of space where most of the story takes place - lies in between the Ctarl-Ctarl Empire and the Terran Federation, and was established as a buffer zone after numerous battles between the two species. Its position is said to be 50 light years away from earth.
* Bio-Android. An artificially created Human. Despite being an artificial humanoid, they can possess both free will and human emotions as well as the physical need for food and rest (although for unknown reasons, they lack the ability to dream)
* Silgrians. A peaceful race in the Outlaw Star universe which resemble anthropomorphic birds. Physically they are usually at least 180 cm (6 ft) tall, and have necks that can make a 180 degree rotation or can turn their head completely upward. Their eyes also have two lids. It is often noted that the Silgrians are 'too friendly' with human races.
* Corbanites. An industrious race of frog-like amphibians. Their natural habitat is in the water, so in air Corbanites wear environment suits that maintain an aquatic environment to their liking. With their technological advancement, most Corbanites fit their enviro-suits with translators that turn their native Corbonese into the local language.
* Sith. An insectoid race that are so alien to the other humanoid races that any manner of relationship with them is impossible.
* Lorgans. A secretive and distrusting people, the Lorgans are not mentioned much in the series. They apparently have such a strained relationship with the Terrans that the two races just avoid one another.
* Saurians. A bio-engineered race of reptiles created by Terrans by combining different strains of dinosaur DNA. Saurians are tall, powerful, imposing creatures with the intelligence and cunning of a Terran combined with the strength and viciousness of their great lizard ancestors.
* Tenrei Aliens. Small, furry, rabbit like creatures that are only seen in the video introducing Tenrei. When the three wizards arrived on their planet, the pleasant little creatures welcomed them with open arms. They introduced them to the hot springs that held rejuvenating powers. This was their downfall. A seductive female wizard named Urt began opening more hot springs and also bringing in heavy construction equipment to start building hotels and the like. In the rapid expansion of humans across Tenrei, the small aliens were lost and are now presumed extinct.
* Un-named Cactus like race. Only seen in episode 13, "Advance Guard from Another World". These immobile beings use psychic control over other organisms. With this they are able to be moved about by being carried, and perform experiments. The only one seen refers to other races as primitive and tries to make them kill each other when its presence is discovered, except that a bio-android like Melfina is immune to its control and able to kill it instead.