thumb|The official logo used for the series from 2022 onwards|alt=Black text spelling out the words Doctor Who. The "Who" is bold, and is surrounded by a white outline.
The long-running British science fiction television series Doctor Who has featured a large number of characters throughout its history. The show stars its protagonist, the Doctor, an alien who travels in time and space in a time machine known as the TARDIS. When the Doctor dies, they can regenerate, which allows them to survive death, though changes their appearance and personality in the process. The Doctor often travels alongside a number of travelling companions, who often act as major supporting characters and co-protagonists on their travels. The Doctor and their companions often encounter a number of antagonists, as well as a number of villainous alien races and creatures, who they must often stop from achieving villainous agendas.
The series began with William Hartnell's First Doctor in 1963's An Unearthly Child, accompanied by companions Susan Foreman (Carole Ann Ford), Barbara Wright (Jacqueline Hill) and Ian Chesterton (William Russell), The Doctor travels in time and space in their time machine known as the TARDIS, frequently alongside a variety of travelling companions. The Doctor is a member of an alien race known as the Time Lords, and when the Doctor dies, a feature of their Time Lord biology, regeneration, allows the Doctor to survive, albeit with a new face, appearance, and personality. The First Doctor eventually dies of old age while fighting the Cybermen, resulting in his regeneration into the Second Doctor. Predominantly exiled to Earth during his run, he frequently works alongside military organisation UNIT, acting as their scientific advisor,
| data-sort-value="75" |Robot (1974)
| data-sort-value="115" |Logopolis (1981)
| The Thirteenth Doctor develops romantic feelings for her companion Yasmin Khan, though this is cut short by her death by a laser beam while fighting the Master.
| data-sort-value="277" |"The Woman Who Fell to Earth" (2018)
| data-sort-value="300" |"The Power of the Doctor" (2022)
| The Fourteenth Doctor, unlike prior incarnations, does not regenerate when he dies, but instead bi-generates, splitting into two individuals (himself and the Fifteenth Doctor).
| data-sort-value="301" |"The Star Beast" (2023)
| data-sort-value="303" |"The Giggle" (2023)
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| data-sort-value="303" |"The Giggle" (2023)
| data-sort-value="319b" |"The Reality War" (2025)
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| data-sort-value="1965" |Dr. Who and the Daleks (1965)
| data-sort-value="1966" |Daleks' Invasion Earth 2150 A.D. (1966)
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|data-sort-value="2013"|"The Name of the Doctor" (2013)
|data-sort-value="2013"|"The Day of the Doctor" (2013)
| She is depicted as having a "darker" characterisation, and is willing to use weapons if necessary.
|data-sort-value="2020"|"Fugitive of the Judoon" (2020)
|data-sort-value="2025"|"The Story & the Engine" (2025)
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|}
Companions
Companions are those who travel with the Doctor in their adventures through time and space. Companions act as major supporting characters and co-protagonists, and are oftentimes human in comparison to the alien Doctor. Below are a number of the Doctor's companions from throughout the show's history.
{| class="wikitable sortable"
|+
!scope=col | Name
!scope=col class="unsortable" | Description
!scope=col | First appearance
|-
! scope=row data-sort-value="The Master" | The Master
|The Doctor's nemesis, the Master is a major recurring antagonist in the series. Also a Time Lord, the Master is a cunning antagonist who engages in a variety of villainous schemes, and their goals include attempting to take over the world and defeating the Doctor. Like the Doctor, the Master can regenerate, and their schemes and motivations often change depending on the incarnation.
|data-sort-value="55"|Terror of the Autons (1971)
|-
! scope=row data-sort-value="Davros" |Davros
|The megalomaniacal creator of the Dalek race. During a war on his home planet Skaro between his race, the Kaleds, and another race called the Thals, Davros mutated his people into the Daleks to ensure their survival. Davros serves as a recurring foe throughout the series, often alongside the Daleks.
|data-sort-value="78"|Genesis of the Daleks (1975)
|-
! scope=row data-sort-value="The Mara" | The Mara
|A gestalt, non-corporeal entity that preys upon people through their dreams. It was created from the darkness in the hearts of humans, and hails from a realm known as "The Dark Places of the Inside", which it is bound to and continually attempts to escape from.
|data-sort-value="118"|Kinda (1982)
|-
! scope=row data-sort-value="Rassilon" |Rassilon
|A mythical figure in Time Lord society, Rassilon aided in the conception of time travel technology that pioneered the Time Lords to power, becoming its "Lord High President" after fellow inventor Omega was lost during its creation. Though dying before the series began, he is later revived, serving as an antagonist in later appearances.
|data-sort-value="129"|"The Five Doctors" (1983)
|-
! scope=row data-sort-value="The Rani" | The Rani
|An amoral Time Lord scientist, exiled from Gallifrey due to the dangers of her experiments, the Rani seeks to continue her experiments, which she is willing to achieve at any cost. The Rani, like the Doctor, also has multiple incarnations, with one of them bi-generating and serving as antagonists in the revival's fifteenth series.
|data-sort-value="139"|The Mark of the Rani (1985)
|-
! scope=row data-sort-value="The Valeyard" | The Valeyard
|During the show's twenty-third season, set during a season-long overarching story arc where the Sixth Doctor is put on trial by the Time Lords, the Valeyard serves as the court prosecutor, attempting to find the Doctor guilty. The Valeyard is eventually revealed to be an "amalgamation of the darker sides" of the Doctor's nature from somewhere toward the end of the Doctor's life.
|data-sort-value="143"|The Mysterious Planet (1986)
|-
! scope=row data-sort-value="Cassandra"|Cassandra
|Cassandra is a human from the far future. Driven by vanity and a desire to be beautiful above all else, she has undergone many surgeries, eventually being left as nothing more than a stretched piece of skin on a frame. She encounters the Doctor twice; in the first, she attempts to kill the passengers of a space station to collect their insurance money, while in the second, she attempts to possess and steal Rose's body.
|data-sort-value="196"|"Midnight" (2008)
|}
Aliens and creatures
During the course of the series, the Doctor encounters many creatures, including alien species, with many of them acting as major antagonists or supporting characters.
{| class="wikitable sortable"
|+
!scope=col | Name
!scope=col class="unsortable" | Description
!scope=col | First appearance
|-
! scope=row data-sort-value="Dalek" |Dalek
|Highly xenophobic, militant cyborgs that hail from the planet Skaro. The Daleks seek to conquer the universe and kill all other forms of life. The Daleks were the first alien species featured in the series and have subsequently recurred throughout the series.
|data-sort-value="2"|The Daleks (1963–1964)
|-
! scope=row data-sort-value="Cyberman" |Cyberman
|Cyborgs who originally hail from Earth's twin planet, Mondas. Having cybernetically enhanced themselves to avoid death, they removed all emotion and now seek a variety of goals, including the conversion of other lifeforms into Cybermen.
|data-sort-value="29"|The Tenth Planet (1966)
|-
! scope=row data-sort-value="Yeti" |Yeti
|Robotic minions of the non-corporeal entity known as the Great Intelligence. The Yeti are used by the Intelligence during several of its invasions.
|data-sort-value="38"|The Abominable Snowmen (1967)
|-
! scope=row data-sort-value="Ice Warrior" |Ice Warrior
|A reptilian warrior race from the planet Mars. Bound by an honour code, the Ice Warriors wear bio-mechanical armor that provides protection from attack and hostile temperature changes, as well as providing weaponry. The Time Lords are the race that created time travel in-universe, and, when killed, have the ability to regenerate, which allows them to survive lethal injuries, and causes them to change their physical appearance. The Doctor is one of their number. The Autons are living plastic mannequins, which the Nestene uses as its footsoldiers in its invasions.
|data-sort-value="51"|Spearhead from Space (1970)
|-
! scope=row data-sort-value="Silurian" |Silurian
|rowspan="2" | The Silurians and Sea Devils are a race of reptilian humanoids that hail from Earth. Hailing from the dawn of its history as the original inhabitants of the planet, they put themselves into hibernation to avoid an extinction event, but as the event never occurred, their computers never awoke them, leaving them trapped in hibernation.
|data-sort-value="52"|Doctor Who and the Silurians (1970)
|-
! scope=row data-sort-value="Sea Devil" |Sea Devil
|data-sort-value="62"|The Sea Devils (1972)
|-
! scope=row data-sort-value="Sontaran" |Sontaran
|A clone race from the planet Sontar. Sontarans are war-like and militaristic, taking great pride in battle. They are locked into an eternal war with an alien species known as the Rutans.
|data-sort-value="70"|The Time Warrior (1973–1974)
|-
! scope=row data-sort-value="Zygon" |Zygon
|A race of shapeshifters who hail from the planet Zygor. Their home planet was destroyed, resulting in them seeking out new planets to conquer as a new home.
|data-sort-value="80"|Terror of the Zygons (1975)
|-
! scope=row data-sort-value="Slitheen" |Slitheen
|The Slitheen are a criminal family of Raxicoricofallapatorians, a species who hail from the planet Raxicoricofallapatorius. They are capable of disguising themselves as humans via skin suits, which they use to infiltrate human environments.
|data-sort-value="160"|"Aliens of London" (2005)
|-
! scope=row data-sort-value="Ood" |Ood
|A peaceful race who hail from a planet known as the Ood-Sphere. The Ood, in the past, were enslaved by a company named "Ood Operations", and were sold to humans in the far future as slave labour.
|data-sort-value="174"|"The Impossible Planet" (2006)
|-
! scope=row data-sort-value="Weeping Angel" |Weeping Angel
|A race of aliens who are "quantum-locked", meaning that when observed, they turn to stone, and can only move when unobserved. One touch from a Weeping Angel sends the one touched back in time, with the resultant temporal energy being used by the Angel as a food source.
|data-sort-value="186"|"Blink" (2007)
|-
! scope=row data-sort-value="Silent" |Silent
|A race of beings that can only be perceived while being observed, being instantly forgotten once unobserved. Many are associated with the Silence, an organisation that seeks to kill the Eleventh Doctor.
|data-sort-value="214"|"The Impossible Astronaut" (2011)
|}
Other supporting characters
{| class="wikitable sortable"
|+
!scope=col | Name
!scope=col class="unsortable" | Description
!scope=col | First appearance
|-
! scope=row data-sort-value="UNIT" |UNIT
|A military organisation that recurs throughout the series that specialises in dealing with alien threats. UNIT notably serve as major supporting characters while the Third Doctor is exiled on Earth.
|data-sort-value="46"|The Invasion (1968)
|-
! scope=row data-sort-value="Kate Lethbridge-Stewart" |Kate Lethbridge-Stewart
|The daughter of the Brigadier, Kate later serves as the head of UNIT as well as serving as its chief scientific advisor. Kate serves as a recurring character in the series, and additionally appears as a major character in 2025 spin-off series The War Between the Land and the Sea.
|data-sort-value="155b"|Downtime (1995)
|-
! scope=row data-sort-value="Iris Wildthyme" |Iris Wildthyme
|Initially created as an original character, Wildthyme was incorporated into Doctor Who spin-off media throughout the 1990s, including in her own spin-off series. Iris's irreverent, eclectic character and stories are characterised by her creator, Paul Magrs, as characterising her as someone who cannot "be seen as good or bad, she's just muddling through".
|data-sort-value="155c"|Marked for Life (1995)
|-
! scope=row data-sort-value="Jackie Tyler" |Jackie Tyler
|Mother of Rose Tyler, Jackie serves as a major recurring supporting character during Rose's travels with the Doctor. Jackie becomes involved in a number of the Ninth Doctor and Rose's adventures, assisting them on several occasions.
|data-sort-value="157"|"Rose" (2005)
|-
! scope=row data-sort-value="Harriet Jones" |Harriet Jones
|Originally the MP of the fictional Flydale North, Harriet Jones ends up becoming the Prime Minister of England. After she orders the destruction of an alien ship, the Doctor manipulates her fall from power, and she later dies fighting the Daleks.
|data-sort-value="160"|"Aliens of London" (2005)
|-
! scope=row data-sort-value="Torchwood Institute" |Torchwood Institute
|The Torchwood Institute is an organisation created by Queen Victoria to protect the United Kingdom from what are deemed alien threats, including the Doctor. The Institute is later taken over by former companion Jack Harkness, who seeks to steer it away from its past roots, with this version being the main focus of the spin-off series Torchwood.
|data-sort-value="177"|"Army of Ghosts" (2006)
|-
! scope=row data-sort-value="Church of the Papal Mainframe" |Church of the Papal Mainframe
|The Church of the Papal Mainframe is an interstellar, militant church that hails from the 51st century. The Church acts akin to a "security hub", despite being a religious order, with the Church seeking to protect innocents.
|data-sort-value="206"|"The Time of Angels" (2010)
|-
! scope=row data-sort-value="Paternoster Gang" |Paternoster Gang
|A trio consisting of the Silurian Madame Vastra, human Jenny Flint, and Sontaran Strax. Jenny and Vastra are in a lesbian relationship, with Strax acting as their butler. The trio work together in Victorian London, where they solve mysteries.
|data-sort-value="218"|"A Good Man Goes to War" (2011)
|-
! scope=row data-sort-value="Danny Pink" |Danny Pink
|A man who acts as companion Clara Oswald's boyfriend during the revival's eighth series. A former soldier, Danny works as a maths teacher in the school where Clara works.