Star Trek is a science fiction media franchise that began with Gene Roddenberry's launch of the original Star Trek television series in 1966. Its success led to numerous films, novels, comics, and spinoff series. A major motif of the franchise involves encounters with various alien races throughout the galaxy. These fictional alien races are listed here.

Notable Star Trek races include Vulcans, Klingons, and the Borg. Some aspects of these fictional races became well known in American pop culture, such as the Vulcan salute and the Borg phrase, "Resistance is futile."

Star Trek aliens have been featured in Time magazine, which described how they are essential to the franchise's narrative.

Key

A RaceDescriptionEpisodes (M = mention only)Aenar Andoria, Alpha Quadrant"United" (ENT), "Strange New Worlds" (SNW)Aenar, along with the Andorians, inhabit the world of Andoria. In many regards, they are similar to the Andorians in physical appearance. Unlike the Andorians, their skin is light blue/white, they are almost blind, and they have powerful telepathic abilities. Aenar are pacifistic and do not use their mind-reading abilities against the will of another individual. Their blindness does not appear to hinder their abilities.

Aenar government has little structure; leaders of Aenar society are chosen as the need arises, usually when contact with outsiders is called for. The Aenar are generally considered a different ethnicity of the Andorian race, not a separate species.

The Aenar population is about 11,000 in size, and they inhabit the polar region of their world.

Shran's daughter, Talla, from "These Are the Voyages..." (ENT), is a mixed-race individual of Andorian and Aenar origin and greenish in color, as is the Andorian in Star Trek: The Next Generation.

Hemmer, the first Chief Engineer on the Enterprise in Strange New Worlds, is Aenar.Andorian Andoria, Alpha Quadrant"Journey to Babel" (TOS), "United" (ENT)Andorians are a humanoid species with blue skin and antennae. They consider themselves a warrior race, contrasting with the pacifist Aenar. They are native to the moon Andoria, which orbits the planet Andor. They were a founding member of the United Federation of Planets.Angosian "The Hunted" (TNG)Usually considered non-violent, Angosian authorities were responsible for genetically and chemically engineering soldiers to fight in their Tarsian Wars. Such process was irreversible, and the 'super soldiers' were considered outcasts and criminals that could not coexist alongside the normal population of Angosian society. As such, they were forced to be permanently confined to a penal settlement on an Angosian moon. A non-canon novel trilogy, Star Trek: The Q Continuum, shows that the Angosians have had some success in later efforts to reintegrate the soldiers, as one now serves on the Enterprise-E.Antedean Antede III"Manhunt" (TNG)The Antedeans from Antede III is an ichthyohumanoid species that resemble fish with a strong distaste for space flight. Although the Antedeans are a space-going race, space travel is quite traumatic. For individuals to deal with this problem, they induce a catatonic state while in space flight. To awaken from this state takes several hours. Once awakened from this sleep, Antedeans are generally greedy and eat large portions of vermicula.

The Antedean race is divided over whether membership in the Federation is good.Arcadian Star Trek IV: The Voyage HomeArcadians have large, round, doll-like heads and have hair on the left and right sides of their heads with none in the middle. They are a member of the United Federation of Planets with a representative on the Federation Council. They joined at least as early as the 2280s.Arcturian ArcturusStar Trek: The Motion PictureArcturians are known for their clones, which have the appearance of melted skin and hail from the densely populated world Arcturus.

Nothing has been revealed about them in dialogue, so their backstory (by Fred Phillips and Robert Fletcher) is considered semi-canon.Axanar "Fight or Flight" (ENT), "Whom Gods Destroy" (TOS) MThe Axanar are the first extraterrestrial race befriended by Earth people aboard the NX-01 Enterprise.

One of James T. Kirk's earliest commendations is the Palm Leaf of Axanar Peace Mission, following the Battle of Axanar; However, the exact nature of the conflict is unrevealed; it is revealed in the episode "Whom Gods Destroy" that Starfleet Captain Garth of Izar achieved a great victory on behalf of the Federation, and his strategies became required reading at Starfleet Academy (since Kirk himself studied these strategies, the Battle of Axanar must thus have occurred well before Kirk entered Starfleet Academy in 2250, which was itself almost 20 years before "Whom Gods Destroy"). Kirk claims that the Axanar Peace Mission "topped [Garth's victory] with a greater one" and preserved the civilization that made Spock and himself "brothers," implying that the mission may have contributed to healing a severe rift in the Federation at that time.

B RaceDescriptionEpisodes (M = mention only)Bajoran Bajor (M-class)"Ensign Ro" (TNG) "Emissary" (DS9)The Bajorans are a humanoid species with characteristic nose creases. They live on the planet Bajor. They are deeply spiritual people who worship The Prophets. They are enemies of the Cardassians, who occupied Bajor and treated the Bajorans as enslaved in the early 24th century. Time Magazine called the Bajorans "a proud people struggling to recover from another species's hostile occupation of their world."Ba'ku Unknown, The Briar PatchStar Trek: InsurrectionThe Ba'ku people were a technologically advanced humanoid civilization. In the early 21st century, the race developed the means of building weapons of mass destruction and was on the brink of self-annihilation. A small enlightened group of the Ba'ku people escaped this horror and found an isolated planet.

This group of Ba'ku followed a simple way of life and disdained the use of technology. (As shown in the film Star Trek: Insurrection, however, the Ba'ku still possessed some form of technology and the ability to use it in emergencies since they had attempted to repair the damaged Data.) At first, the Ba'ku were unaware of the metaphasic radiation in the planet's rings, which caused their aging process to decelerate significantly, although it was later discovered and cherished.

The Ba'ku society consisted of strong bonds between individuals, as fewer than a thousand lived in a village. Their more straightforward way of life eventually prompted some of the younger Ba'ku villagers – who wanted to explore the galaxy with off-landers – to rebel against their elders, and an attempt was made to take over the village. When they were unsuccessful, they were exiled and eventually became the Son'a people.

In 2375, peace on the Ba'ku planet was restored, and several members of the Son'a returned to their families.Benzite Benzar"Coming of Age", "A Matter of Honor" (TNG) Benzites are a humanoid race from the planet Benzar, a member of the United Federation of Planets.

Benzites possess smooth, hairless skin; they may range in color from bluish-purple to green-blue. A thick protrusion of the Benzite skull extends down over the face, displaying a prominent nasal lobe and brow. Two fish-like barbels droop down from above the upper lip. Benzites are highly resistant to poisons and other harmful substances. They can digest and derive nutrition from almost any organic compound. All Benzites from the same geostructure are physically similar, so much so that they are indistinguishable by non-Benzites.Betazoid Betazed"Encounter at Farpoint" (TNG) "Tin Man" "Caretaker" (VOY) "Empathological Fallacies" (LOW) The Betazoid are a humanoid species originating from the planet Betazed, a member of the United Federation of Planets. They are telepathic. Star Trek: The Next Generation features Counsellor Deanna Troi, a half-Betazoid half-human, as a prominent cast member and part of the bridge crew. She is featured in almost all TNG episodes and movies, and several episodes focus on the Betazoid people. These include shows with her mother, Lwaxana Troi. Her romantic interests, family, and personal life are plot elements in many Star Trek: The Next Generation episodes throughout the series. Episodes usually feature Troi using her telepathic abilities to help the crew better understand enemies and allies. Customs: The word Imzadi, meaning 'Beloved,' is often used between a Betazoid and their partner, whether they are of the same species or not. Betazoid weddings are conducted with the bride, groom, and several participants completely naked. The newlyweds possibly remain so for the duration of the honeymoon (TNG episode "Haven," novel The Persistence of Memory). A Betazoid woman's sex drive quadruples (at the least) when she reaches a certain age (TNG episode "Manhunt").Bolian Bolarus IX"Conspiracy" (TNG) "Emissary" (DS9) "Caretaker" (VOY) Bolians are humanoids with blue skin and a small ridge running from the back of their heads to their noses. They were named after a regular Star Trek director, Cliff Bole. As an in-joke, there have been references to the "Cliffs of Bole" on their planet. Neelix remarks that malfunctioning toilets will mainly affect the Bolians. During medical examinations, 24th-century doctors commonly ask if a human patient has had sexual relations with a Bolian.

The Bolian world has been an active member of the Federation since 2320. Aside from contributing to the ranks of Starfleet, they have a delegation within the Diplomatic Corps. In 2366, the Bolian government was maintaining an uneasy truce with the Moropa (TNG: "Allegiance").

The Bolians are known to make crystal steel that is highly prized. They also own and operate the famous Bank of Bolius. In 2373, the Bolian government authorized the Ferengi Gaming Commission to manage their gambling emporiums.

During the Bolian Middle Ages, the Bolians developed the medical philosophy known as the "Double Effect Principle" about euthanasia. This form of assisted suicide states that while euthanasia has the effect of relieving suffering, it also has the effect of causing death. Bolian marriages often involve more than two members. Any additional spouse is referred to as a "co-husband" or "co-wife." Bolian blues is a highly appreciated musical genre among Federation species.Borg Unknown"Q Who?" (TNG) "The Best of Both Worlds" (TNG) "I, Borg" (TNG) "Descent." (TNG) "Scorpion" (VOY) "Unimatrix Zero" (VOY) "Endgame" (VOY) "Regeneration" (ENT) Star Trek: First ContactWhile encountered in the Enterprise episode "Regeneration," the Borg, a pseudo-species of cybernetically enhanced individuals, were not fully identified as the single greatest threat to the Federation until the events of The Next Generation episode "Q Who?". The Borg were discovered to be a group without individuality, where every member is a part of a collective consciousness in an attempt to achieve perfection. They assimilate any species they come into contact with for either biological aspects (for example, Talaxians would be incorporated for their dense physical structure, helpful in producing solid and resilient drones) or technological aspects (a species that has developed advanced engines or weaponry would be a sufficiently desirable target for assimilation) all in an attempt to improve further the overall perfection of the Borg as a whole.

The Borg have encountered and assimilated thousands of species, quantity most notable by their designation of Species 8472, although more may have been added to the total since that encounter.

The Borg are not a species but a collection of species. In their assimilated state, most races are altered or augmented with cybernetic enhancements that make them all look similar or instantly identifiable as Borg, making them a pseudo-species.