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.
Key
A
{| class="wikitable"
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!Race
!Description
!Episodes (M = mention only)
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| rowspan="2" style="vertical-align: top;"|Aenar <br />
| Andoria, Alpha Quadrant
| rowspan="2" style="vertical-align: top;"|"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.
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| rowspan="2" style="vertical-align: top;"|Andorian <br />
| Andoria, Alpha Quadrant
| rowspan="2" style="vertical-align: top;"|"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.
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| rowspan="2" style="vertical-align: top;"|Angosian <br />
|
| rowspan="2" style="vertical-align: top;"|"The Hunted" (TNG)
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|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.
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<!-- Antedean and Antedeans link here. Please only delete or rename this section after FIRST, correcting all incoming links. -->
| rowspan="2" style="vertical-align: top;"|Antedean <br />
| Antede III
| rowspan="2" style="vertical-align: top;"|"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.
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<!-- Arcadian (Star Trek), Arcadians (Star Trek) and List of fictional alien species: A link here. Please only delete or rename this section after FIRST, correcting all incoming links. -->
| rowspan="2" style="vertical-align: top;"|Arcadian <br />
|
| rowspan="2" style="vertical-align: top;"|Star Trek IV: The Voyage Home
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|Arcadians 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.
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| rowspan="2" style="vertical-align: top;"|Arcturian <br />
| Arcturus
| rowspan="2" style="vertical-align: top;"|Star Trek: The Motion Picture
|-
|Arcturians 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.
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| rowspan="2" style="vertical-align: top;"|Axanar <br />
|
| rowspan="2" style="vertical-align: top;"|"Fight or Flight" (ENT), "Whom Gods Destroy" (TOS) M
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|The 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.
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B
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! rowspan="2"|Race
! Home planet
! rowspan="2"|Episodes (M = mention only)
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!Description
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| rowspan="2" style="vertical-align: top;"|Bajoran
| Bajor (M-class)
| rowspan="2"|"Ensign Ro" (TNG) <br> "Emissary" (DS9)
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|
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." First-known examples are both young: 8-year-old Rok-Tahk from Star Trek: Prodigy, and young adult Zak Kebron from the Star Trek: New Frontier series of novels. According to the novelization, Brikar experience puberty later than humans.
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C
{| class="wikitable"
! rowspan="2"|Race
!Home planet
! rowspan="2"|Episodes (M = mention only)
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!Description
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| rowspan="2" style="vertical-align: top;"|Cardassian
|Cardassia Prime, Alpha Quadrant
| rowspan="2"|Introduced in "The Wounded" (TNG); many TNG/DS9/VOY appearances.
|-
|
The Cardassians are enemies of the United Federation of Planets and are mentioned in Star Trek: Deep Space Nine, Star Trek: The Next Generation, and Star Trek: Voyager. They have noticeable ridges along their foreheads and necks and a crest on their foreheads, earning them the nickname, Spoonheads. Their government is a military dictatorship.
Production design: Their makeup design was done by Michael Westmore, and their costumes by Robert Blackman.
Major Cardassian characters: Garak, Gul Dukat.
|-
| rowspan="2" style="vertical-align: top;"|Chameloid
|Unknown
| rowspan="2"|Star Trek VI: The Undiscovered Country, Martia
Star Trek: Section 31, Quasi
|-
|A race of shapeshifters who can assume any form, the first appearance was in the form of Martia, a prisoner in the Klingon prison colony of Rura Penthe, whom Kirk and McCoy encounter when they are imprisoned there. Prior to this, Kirk stated that he thought Chameloids were merely mythical.
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| rowspan="2" style="vertical-align: top;"|Changeling
|Unknown, Gamma Quadrant
| rowspan="2"| Odo, Seasons 1–7 (DS9)
|-
|A race of fluid shapeshifters,
|-
| rowspan="2" style="vertical-align: top;"|Deltan
|Delta IV, Alpha Quadrant
| rowspan="2"|Star Trek: The Motion Picture, Ilia
Star Trek: Section 31, Melle
|-
| The Deltans are a humanoid species originating from the Federation planet Delta IV and are outwardly indistinguishable from humans, except that they are bald and wear headdresses. They are known for their strong sexual attraction, which can be distracting to members of other species, leading Deltans to take a vow of chastity upon joining Starfleet.
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| rowspan="2" style="vertical-align: top;"|Douwd
|Unknown
| rowspan="2"|"The Survivors" (TNG)
|-
| Immortal energy beings with vast powers. Only one is known to exist, choosing to live alone in human form on the planet Delta Rana IV. That one committed xenocide against the Husnock.
According to Time Magazine, Captain Picard found the Douwd he met an alien "being of extraordinary power and conscience" and felt they should be left alone. Passing references to Edosian flora and fauna have been made in episodes of Star Trek: Deep Space Nine and Star Trek: Enterprise. In some tie-in novels and short stories, Arex is mentioned as a Triexian, with the Edosians being a near-identical race.
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| rowspan="2" style="vertical-align: top;"|El-Aurian
|El-Auria, Delta Quadrant
| rowspan="2" |"Rivals" (DS9)
|-
|El-Aurians (referred to as a Race of Listeners by Dr. Tolian Soran, the El-Aurian antagonist in Star Trek Generations) are a humanoid race first introduced in the second season of Star Trek: The Next Generation with the character Guinan. The species was named in the Star Trek: Deep Space Nine episode "Rivals."
El-Aurians appear outwardly identical to humans and have a variety of ethnic types, with both dark- and light-skinned members of the race being shown in various Star Trek movies and television episodes. They can live well over 700 years. They are considered a race of listeners and often appear patient and wise.
El-Auria, the El-Aurian homeworld, was located in the Delta Quadrant and was destroyed by the Borg in the mid-23rd century. Few survived, and those who did were scattered throughout the galaxy. Some of the refugees came to the United Federation of Planets.
|}
F
{| class="wikitable"
! Race
!Home planet
! rowspan="2"|Episodes (M = mention only)
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!Image
!Description
|-
| rowspan="2" style="vertical-align: top;"|Ferengi <br />120x157px
| Ferenginar, Alpha Quadrant
| rowspan="2" style="vertical-align: top;"|"The Last Outpost" (TNG) and several later episodes <br /> Many (DS9) episodes <br />"False Profits" (VOY)<br /> "Mugato, Gumato" (LOW)<br /> "Parth Ferengi's Heart Place" (LOW)
|-
|
At the start of Star Trek: The Next Generation, the Ferengi are considered a mysterious race who care only about profit. They feature as major characters in Deep Space Nine.
In 2017, Den of Geek ranked Gorn the 23rd best alien species of the Star Trek franchise.
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H
{| class="wikitable"
! rowspan="2"|Race
!Home planet
! rowspan="2"|Episodes (M = mention only)
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!Description
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| rowspan="2" style="vertical-align: top;"|Hirogen
| Unknown, Delta Quadrant
| rowspan="2"|"Message in a Bottle"(VOY)<br/>"Hunters" (VOY)<br />"Prey" (VOY)<br />"The Killing Game" Parts 1 & 2 (VOY)<br />"Tsunkatse" (VOY)<br />"Flesh and Blood" Parts 1 & 2 (VOY)
|-
|The Hirogen are a violent Delta quadrant species encountered by the USS Voyager. The Hirogen culture is based around hunting other sentient species, whom they regard as "prey." They are humanoid but larger than humans.
; Reception
In 2017, ScreenRant ranked the Hirogen the 10th most bizarre aliens in the Star Trek franchise up to that time.
|}
I
{| class="wikitable"
! rowspan="2"|Race
!Home planet
! rowspan="2"|Episodes (M = mention only)
|-
!Description
|-
| rowspan="2" style="vertical-align: top;"|Illyrian
| Illyria
| rowspan="2"|"Damage" (ENT)
"Ghosts of Illyria" (SNW)
"Ad Astra per Aspera" (SNW)
|-
|The Illyrians are a species first encountered by the Enterprise NX-01. They are a race that holds genetic augmentation as a tradition, with their species adapting themselves genetically to be able to survive almost anywhere.
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J
{| class="wikitable"
! rowspan="2"|Race
!Home planet
! rowspan="2"|Episodes (M = mention only)
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!Description
|-
<!-- Jem 'Hadar, Jem hadar, and Jem'Hadar link here. Please only delete or rename this section after FIRST, correcting all incoming links. -->
| rowspan="2" style="vertical-align: top;"|Jem'Hadar
| Unknown, Gamma Quadrant
| rowspan="2"|"The Jem'Hadar" (DS9); Star Trek: Deep Space Nine passim
|-
|The Jem'Hadar feature in Star Trek: Deep Space Nine, first introduced in the episode "The Jem'Hadar". They are the shock troops of the powerful Dominion, located in the Gamma Quadrant. Genetically engineered for strength and resolve, they are also short-lived and believe that "victory is life". They are bred to perceive the Founders – enigmatic shape shifters who rule the massive Dominion – as gods and are incapable of harming them. The Jem'Hadar are noted as being able to camouflage themselves with their surroundings and depend upon the drug Ketracel White, a substance made and distributed by the Founders as a means of control; their ships have no chairs, replicators, or medical facilities. The Jem'Hadar's numbers are unknown, but they are produced by the thousands as needed.
Conceived as "more than just another fearsome alien", the Deep Space Nine makeup department searched for concepts depicting "toughness and resiliency" in the design of the Jem'Hadar. The final design was based on a rhinoceros, with some added ceratopsian traits. Originally designed on the premise that they were all clones, the first Jem'Hadar seen onscreen were all made to look identical to one another. However, as they became more deeply woven into the storylines, each Jem'Hadar was given a distinctive look.
In 2017, ScreenRant ranked the Jem'Hadar as the 8th most bizarre aliens in Star Trek.
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| rowspan="2" style="vertical-align: top;"|Kzinti
| Kzin
| rowspan="2"|"The Slaver Weapon" (TAS)
|-
|
The Kzinti had originally appeared in the Known Space series by Larry Niven and then in the TAS episode "The Slaver Weapon", based on Niven's short story "The Soft Weapons". The cat-like Kzinti had four wars with humanity. According to Sulu, the last one was 200 years before their appearance in the episode. In the Star Trek: Picard episode Nepenthe, Riker says that Kzinti are present on the titular planet.
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L
{| class="wikitable"
! rowspan="2"|Race
! Home planet
! rowspan="2"|Episodes (M = mention only)
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!Description
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| rowspan="2" style="vertical-align: top;"|Lanthanite
| Unknown
| rowspan="2"|Introduced in "The Broken Circle" (SNW).
"Kids These Days" (SFA)
|-
|
The Lanthanites were introduced in the person of Chief Engineer Pelia in the first episode of the second season of Star Trek: Strange New Worlds. Captain Nahla Ake, portrayed by Holly Hunter in Star Trek: Starfleet Academy, is half-Lanthanite.
|-
|}
N
{| class="wikitable"
! rowspan="2"|Race
! Home planet
! rowspan="2"|Episodes (M = mention only)
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!Description
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| rowspan="2" style="vertical-align: top;"|Nausicaan
| Nausicaa, Beta Quadrant
| rowspan="2"|Introduced in "Tapestry" (TNG).
|-
|
The Nausicaans are typically portrayed as a brutal and violent people. They are trypically seen as pirates, mercanaries, and bar brawlers.
|-
|}
O
{| class="wikitable"
! rowspan="2"|Race
!Home planet
! rowspan="2"|Episodes (M = mention only)
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!Description
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| rowspan="2" style="vertical-align: top;"|Ocampa
| Ocampa, Delta Quadrant
| rowspan="2"|
|-
|The Ocampa were a humanoid species who lived on the planet Ocampa in the Delta Quadrant. Their early history was shrouded in mystery but their own legends told of a time when they were capable of great mental feats.
About five hundred Ocampan generations before 2371, Nacene explorers from another galaxy inadvertently damaged the atmosphere of the planet Ocampa so badly that all nucleogenic particles were lost, thus rendering the atmosphere incapable of producing rain. The planet rapidly became a desert, a time the Ocampans later remembered as "The Warming". The Nacene left two of their kind behind to "honor the debt that could never be repaid" to the Ocampa. The male Nacene, known as the Caretaker to the Ocampa, led the endangered species through tunnels into a vast underground city constructed especially for them. The Caretaker provided them with food, entertainment, water from subterranean sources, and power from the Caretaker's array nearby in space. The Nacene then sealed the Ocampa in, using a force barrier. The Ocampa ruling Elders were subsequently charged with discovering the wishes of the Caretaker, who had become almost a deity to the Ocampan populace. By the late 21st century, the female Nacene, called Suspiria by the Ocampa, had decided to leave her mate to seek out "more interesting places." She established her own array, with a colony of Ocampa. Despite this, Ocampa history had no tales of any of them leaving or being abducted by aliens. Under Suspiria's guidance, these Ocampa colonists developed their mental talents and eventually created technology capable of increasing their natural life spans to as much as twenty years. This made them arrogant to the point that they might look at other humanoids like they looked at pets.
All Ocampa appeared to be natural telepaths, able to communicate with members of their species and those of other species, as well. Among the more unusual mental abilities exhibited by the Ocampa were eidetic memory, precognition, telekinesis of varying strength, and the ability to sense and manipulate the subatomic level of matter. Tanis, an Ocampa living on Suspiria's array, demonstrated to Kes that she could control the life force in living things, causing them to grow or die as she wished. Tanis also told Kes that the Ocampa could join Suspiria in a subspace layer called Exosia, which he described as a realm of pure thought.
In early 2374, Kes experienced a rapid and uncontrollable blossoming of her mental abilities, possibly due to experiencing intense telepathic contact with the powerfully telepathic Species 8472. Her body and everything around her, including Voyager, began to destabilize at the subatomic level. Kes left the ship and allowed this process to complete itself, apparently evolving into a being of pure energy. She could then move objects through space without need of conventional propulsion, and later exhibited the ability to travel through time. In 2376, an angry and bitter Kes, who returned to her physical form, came back to Voyager and almost destroyed it with her mental powers; only by seeing a recording of herself made before she left Voyager was the timeline changed, Kes calmed down and elected to return to her homeworld.
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| rowspan="2" style="vertical-align: top;"|Organian
| Organia, Alpha Quadrant
| rowspan="2"|"Errand of Mercy" (TOS)<br/>"Observer Effect" (ENT)
|-
|The Organians are incorporeal energy creatures ("pure energy, pure thought"). After the climax of the episode "Errand of Mercy", Spock comments that they are "as far above us on the evolutionary scale as we are above the amoeba." They assumed humanoid form to "interact" with the Federation representatives and the Klingons. They render all weapons belonging to the opposing parties inoperable through extreme heat and then vanish.
The Organians were a race of beings who had evolved into pure conceptual beings, the essence of thought with no human bodies. In some ways, they were similar to Q for power levels and abilities. In the novel Q Strike, the Organians appear to observe a battle between members of the Q Continuum and other seemingly omnipotent beings from the Star Trek universe. The original Q identifies them after being asked by Captain Jean-Luc Picard who they are and is rather dismissive, remarking that "compared to their code of noninvolvement, your Prime Directive is practically an incitement to riot."
The Organians also appeared on Star Trek: Enterprise in the episode "Observer Effect", where they observed members of the crew infected with a silicon-based virus to decide whether or not they should make first contact with humans. They did not technically appear onscreen; they only manifested themselves by possessing the bodies of several members of the Enterprise crew.
In 2017, Den of Geek ranked Organians the 20th best aliens of the Star Trek franchise. In 2020, ScreenRant ranked them the 5th smartest aliens of the Star Trek franchise.
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| rowspan="2" style="vertical-align: top;"|Orion
| Orion, Beta Quadrant
| rowspan="2"|"The Cage"(TC)<br/>(TAS)<br/>(DS9)<br/>(VOY)<br/>(DIS)<br/>(ENT)<br/>(LOW)
|-
|
Orions are a green-skinned, humanoid alien species in the Star Trek universe. An Orion was first portrayed as an illusion in the original Star Trek pilot. She was seen as well in the broadcast series when this original pilot was incorporated into a two-part episode (episodes 11 and 12) in the first season. Orions are also portrayed in Star Trek: The Animated Series, Star Trek: Deep Space Nine, Star Trek: Voyager, Star Trek: Discovery, Star Trek: Enterprise, Star Trek: Lower Decks, Star Trek: Picard, as well as the 2009 Star Trek film.
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P
{| class="wikitable"
! rowspan="2"|Race
!Home planet
! rowspan="2"|Episodes (M = mention only)
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!Description
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| rowspan="2" style="vertical-align: top;"|Pakled
| Pakled Planet
| rowspan="2"|"Samaritan Snare" (TNG)<br />"Brothers" (TNG) M<br />"No Small Parts", "The Spy Humongous", "we Duj" (LOW)<br />"First First Contact" (LOW) M.
|-
|The Pakled are a species of spacefaring humanoids who obtain technology from other races (rather than developing it themselves), often through trickery. They first appeared in the TNG episode "Samaritan Snare," where the Pakled ship Mondor feigned needing repairs. After Chief Engineer Geordi La Forge was transported to the Mondor and completed repairs, the Pakled captured him and demanded weapons technologies. The Pakled do not appear again but are mentioned in the TNG episode "Brothers" as the Pakleds inadvertently having rescued Data's brother Lore, who was beamed into space at the end of "Datalore". They appeared again in Star Trek: Lower Decks Season 1 episode "No Small Parts" as the antagonists. The Pakleds, having upgraded their ships using scavenged technology from dozens of species, destroy the U.S.S. Solvang, and cause severe damage to the U.S.S. Cerritos, before being chased away by the Cerritos and U.S.S. Titan commanded by Captain William T. Riker.
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Q
<!-- Lady Q, Q (star trek), Q Continuum, Q Continuum (Star Trek), and Q2 (Star Trek) link here. Please only delete or rename this section after FIRST, correcting all incoming links. -->
{| class="wikitable"
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!Home planet
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!Description
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| rowspan="2" style="vertical-align: top;"|Q
| Unknown
| rowspan="2"|"Encounter at Farpoint", "Q Who", "Deja Q", "Hide and Q", "Devil's Due", "Qpid", "True Q", "Tapestry", "All Good Things..." (TNG)<br />"Q-Less" (DS9)<br />"Death Wish", "The Q and the Grey", "Q2" (VOY)<br />"Cupid's Errant Arrow" (LOW) M<br />"Veritas" (LOW)
|-
|
The Q are immortal, seemingly omnipotent creatures, all named Q. Q is their collective name and the name of their Continuum. One Q is particularly interested in humanity and enjoys repeatedly causing trouble for Captains Picard and Janeway and once for Sisko. The proper Q form is never seen as they claim other races cannot comprehend it.
The Q was introduced on Star Trek: The Next Generation.
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R
{| class="wikitable"
! rowspan="2"|Race
!Home planet
! rowspan="2"|Episodes (M = mention only)
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!Description
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<!-- Reman starships, and Rhinasu Galæ link here. Please don't delete or rename this section without FIRST correcting all incoming links. -->
| rowspan="2" style="vertical-align: top;"|Romulan
| Romulus, Beta Quadrant (historically, Vulcan in the Alpha Quadrant)
| rowspan="2"|"Balance of Terror", "The Enterprise Incident (TOS)<br />"The Deadly Years" (TOS) M<br />Star Trek: Nemesis<br />(PIC)
|-
|
Romulans are humanoid extraterrestrials that appear in the Star Trek television series, where members of their race often serve as antagonists. They are a violent, treacherous offshoot of the Vulcans and rule the militaristic Romulan Empire.
They prominently feature in the film Star Trek: Nemesis.
|-
| rowspan="2" style="vertical-align: top;"|Reman
| Remus, Beta Quadrant
| rowspan="2"|Star Trek: Nemesis<br />"United", "The Aenar" (ENT)
|-
|Remans are a humanoid caste related to the Romulans, forced to live as enslaved under the Romulans and work in the hazardous dilithium mines on Remus. They also prominently feature in Star Trek: Nemesis.
|}
S
{| class="wikitable"
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!Home planet
! rowspan="2"|Episodes (M = mention only)
|-
!Description
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| rowspan="2" style="vertical-align: top;"|Son'a
| Unknown, The Briar Patch
| rowspan="2"|Star Trek: Insurrection
|-
|
Once members of the neo-luddite race the Ba'ku, the Son'a were exiled from their home planet by their fellows for trying to overthrow the leadership and embracing more advanced technology. Now separated from the rejuvenating properties of the Ba'ku planet, they attempt to avoid death through medical procedures. The Son'a use of certain technology, including isolytic-burst weaponry, was banned within the Federation. Nonetheless, in 2375 the Federation allied with the Son'a to take advantage of their technology to gather rejuvenating 'metaphasic particles' emanating from the rings of the Ba'ku planet, which is in Federation space. After the operation, which involved the forced relocation or genocide of the Ba'ku, was called into question and stopped by the crew of the Enterprise, a number of the Son'a reintegrated into the Ba'ku population. Others later joined the Dominion. The Son'a have subjugated two peoples as their slaves: the Ellora and the Tarlac.
|-
| rowspan="2" style="vertical-align: top;"|Species 8472
| Unknown, Fluidic Space
| rowspan="2"|"Scorpion Part 1 & 2", "Prey", "In the Flesh" (VOY) "Unimatrix Zero Part 2", "Someone to Watch Over Me", "The Omega Directive", "Q2" (VOY) M
|-
|
Species 8472 appeared in four episodes of Star Trek: Voyager. While passing through Borg space, Voyager encounters Species 8472, a race that surpasses the Borg in combat prowess.
|}
T
{| class="wikitable"
! rowspan="2"|Race
!Home planet
! rowspan="2"|Episodes (M = mention only)
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!Description
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| rowspan="2" style="vertical-align: top;"|Talaxian
| Talax, Delta Quadrant
| rowspan="2" |"Dragon's Teeth", "Jetrel", "Fair Trade", "Homestead", "The Raven", "Investigations", "Basics Part II","Caretaker", "Random Thoughts" (VOY)
|-
|On Star Trek: Voyager, the ship's cook Neelix is a Talaxian, first appearing in "Caretaker".
In 2017, Den of Geek ranked Talaxians the 21st best aliens of the Star Trek franchise.
|-
| rowspan="2" style="vertical-align: top;"|Talosian
| Talos IV, Alpha Quadrant
| rowspan="2" |"The Cage", "The Menagerie" (TOS), "If Memory Serves" (DIS)
|-
|The Talosians were the first race encountered in the Star Trek franchise.
They are a race that used to be technologically advanced and warp-capable, but a nuclear holocaust devastated their homeworld.
The Talosians are noted for their power of illusions.
In 2017, Den of Geek ranked Talosians the 16th best aliens of the Star Trek franchise.
|-
| rowspan="2" style="vertical-align: top;"|Tellarite
| Tellar Prime, Alpha Quadrant
| rowspan="2" |"Journey to Babel", "Whom Gods Destroy" (TOS), "The Time Trap" (TAS), "Carbon Creek", "Babel One", "Dead Stop", "Civilization", "Bounty", "Borderland", "United", "Terra Prime" (ENT), "Dream Catcher", (PRO) "The Red Angel", "Through the Valley of Shadows" (DIS)
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|The Tellarites have a facial appearance created by having the actors wearing converted pig masks. Culturally, they are known for their love of arguing and blunt, forceful speech, which most other cultures would consider rude; if Tellarite speech is answered in kind, they will typically consider it an honor.
Tellarites appeared rarely in the TNG-era shows, but on Enterprise they are a significant part of several episodes, becoming one of the founding species of the United Federation of Planets. They also appear in Discovery, in which Gorch, a Tellarite Starfleet admiral, is depicted. The animated series Lower Decks depicted a Tellarite captain in the episode "Moist Vessel." In the animated series Prodigy one of the main characters, Jankom Pog, is a 16-year-old Tellarite.
In 2017, Den of Geek ranked Tellarites the 25th best aliens of the Star Trek franchise.
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| rowspan="2" style="vertical-align: top;"|Tholian
| Unknown, Alpha Quadrant
| rowspan="2" |"The Tholian Web" (TOS), In a Mirror, Darkly, " "Future Tense" (ENT)
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|The Tholians are an extremely xenophobic, non-humanoid hermaphroditic species with a propensity for precision. They first appear in the original series episode, "The Tholian Web", where Spock remarks when fired upon by the Tholians: "The renowned Tholian punctuality." Tholian biology required high temperatures around 480 Kelvin (207 °C, 404 °F). They could tolerate lower temperatures for a brief period; if they were exposed to temperatures around 380 Kelvin or less, their carapace would crack. This was painful or distressing; a Tholian subjected to such a temperature regime could be coerced to cooperate. In temperatures even lower, a Tholian would freeze solid and shatter.
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| rowspan="2" style="vertical-align: top;"|Tribble
| Iota Geminorum IV, Beta Quadrant
| rowspan="2" |"The Trouble with Tribbles" (TOS), "More Tribbles, More Troubles" (TAS), "Trials and Tribble-ations" (DS9), "The Breach" (ENT), "Context is for Kings", "Despite Yourself" (DIS), "The Bounty" (PIC), "No Small Parts (LOW)
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Tribbles are a small, harmless species noted primarily for their ability to reproduce extremely quickly; this rapid reproduction creates massive Tribble colonies which can be dangerous to any ecosystem. Though they are normally extremely docile and produce a unique purring sound in the presence of humanoid species that elicits a calming effect, Tribbles produce a shrill shrieking sound in the presence of Klingons.
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| rowspan="2" style="vertical-align: top;"|Trill
| Trill, Alpha Quadrant
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|The Trill are a humanoid species. A small minority, after a rigorous selection process, are permitted to join with a sentient, intelligent symbiont. The symbiont is long-lived and can pass from host to host, carrying all the prior host's memories, skills, and experiences. Trill symbionts are also capable of joining with human hosts.
The Trill made their debut on television in the Star Trek: The Next Generation episode "The Host" (May 11, 1991) and were further developed in Star Trek: Deep Space Nine. The Trill Jadzia Dax is the 8th host of the symbiont Dax, and together they are one of the main characters of Deep Space Nine for the first six seasons; when Jadzia is killed, Ezri Dax, becomes the next Dax host for the seventh and final season. This species was also briefly represented as a holonovel character corresponding to Ensign Harry Kim on Star Trek: Voyager in "Author, Author" (April 18, 2001).
Adira Tal, a human joined with a Trill symbiont, appears in the third season of Star Trek: Discovery. A Trill doctor, Naáshala Kunamadéstifee, appears in Star Trek: Picard, and several Trill also feature in Lower Decks.
Trill have been studied in analyzing the biology of Star Trek, especially regarding the symbionts.
There are two contrasting concepts for Trill. One is that a symbiont is essentially an alien person; nonetheless, the joined Trill still mixes the original person with the memories and some of the personality of the symbiont. This concept was explored in the Star Trek: Deep Space Nine television episode "Dax." The symbionts have been dismissed as "just memories" rather than an actual person, although in other cases they are described as a "sentient symbiotic organism.")
- Primates: The Chairman, Degra
- Reptilians: regimental commander Dolim
Other significant Xindi characters
- Kessick – Primate, enslaved on a Trellium-D mine
- Thalen – Primate, Degra's assistant
- Gralik – Arboreal, chief technician of kemocite facility
Reception
In 2017, ScreenRant ranked the Xindi the 13th most bizarre aliens in Star Trek.