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), with the series' very first alien antagonists, the Daleks, who debuted in the subsequent serial, The Daleks (1963-64). Since then, the show has featured a revolving cast, with the Doctor regenerating into new forms and with new companions, antagonists, and characters being introduced throughout the show's run.

The Doctor

The Doctor is the main character of Doctor Who, a long-running British science fiction television series. 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.

Main incarnations

+ Incarnation Characteristics Main appearances Primary actor First Last First DoctorDepicted as an old man, he is characterised as an "elderly curmudgeon" with moments of empathy, as well as a deep care for his granddaughter, Susan Foreman. The First Doctor eventually dies of old age while fighting the Cybermen, resulting in his regeneration into the Second Doctor.An Unearthly Child (1963)The Tenth Planet (1966) Second DoctorDescribed as a "cosmic hobo" by viewers, the Second Doctor hides his vast intellect behind a more comedic exterior. The Second Doctor is characterised as a defender of the innocent, and eventually dies after his people, the Time Lords, exile him to Earth and force him to regenerate.The Power of the Daleks (1966)The War Games (1969) Third DoctorThe Third Doctor is depicted as a suave, authoritative, and moralistic figure, being a James Bond-esque character with a penchant for gadgets and vehicles. Predominantly exiled to Earth during his run, he frequently works alongside military organisation UNIT, acting as their scientific advisor, while also dueling his rival, an antagonistic Time Lord named the Master. The Third Doctor later regenerates after being exposed to a lethal dose of radiation.Spearhead from Space (1970)Planet of the Spiders (1974) Fourth DoctorThe Fourth Doctor is a free spirit, and is very eccentric in nature, often feigning being a fool to catch those around him off-guard. He is well known for wearing a distinctive long scarf. The Fourth Doctor was the longest-serving incarnation of the character, and thus is widely considered to be the most iconic of the Doctor's incarnations. The Fourth Doctor regenerates after falling off a radio telescope while fighting the Master.Robot (1974)Logopolis (1981) Fifth DoctorThe Fifth Doctor is characterised as having a youthful energy, and is depicted as often being more emotionally vulnerable as a result. The Fifth Doctor regenerates after dying from a poison.Castrovalva (1982)The Caves of Androzani (1984) Sixth DoctorA heroic and caring incarnation, the Sixth Doctor is nonetheless characterised as having low patience and actively fighting with his companion, Peri Brown, as well as being highly egotistical. The Sixth Doctor regenerates after hitting his head.The Twin Dilemma (1984)The Ultimate Foe (1986) Seventh DoctorAt first depicted as a buffoonish figure, the Seventh Doctor's character evolves as he is depicted as a cunning and ruthless master manipulator throughout his adventures. After walking into a gunfight in San Francisco, he is killed during the subsequent surgery operation intended to save his life.Time and the Rani (1987)Survival (1989) Eighth DoctorA soft-spoken character who feels deeply about the world, he is depicted as a "romantic", with his incarnation being the first to engage in romance. The Eighth Doctor regenerates after crash-landing on the alien planet Karn.Doctor Who (1996)"The Night of the Doctor" (2013) Ninth DoctorThe Ninth Doctor is depicted as suffering from trauma after fighting in a devastating interstellar conflict known as the Time War, but finds purpose in his life after befriending his companion, Rose Tyler. He regenerates after absorbing the time vortex to save Rose's life."Rose" (2005)"The Parting of the Ways" (2005) Tenth DoctorThe Tenth Doctor is characterised as youthful, with an eccentric character. He is also depicted as engaging in a romantic relationship with Rose. He regenerates after taking a lethal amount of radiation to save the life of his companion, Wilfred Mott."The Christmas Invasion" (2005)"The End of Time" (2009–2010) Eleventh DoctorDescribed as an "old man trapped in a young man's body," according to showrunner Steven Moffat, the Eleventh Doctor is highly energetic, often having a penchant for different accessories such as fezzes or bow ties. The Eleventh Doctor regenerates after dying of old age."The Eleventh Hour" (2010)"The Time of the Doctor" (2013) Twelfth DoctorBeing visibly older than several of his prior incarnations, he is depicted as being much more "alien" and volatile, but slowly learns to regain a "human" way of acting due to his companions Clara Oswald and Bill Potts. The Twelfth Doctor regenerates while fighting the Cybermen."Deep Breath" (2014)"Twice Upon a Time" (2017) Thirteenth DoctorThe first of the Doctor's female incarnations, the Thirteenth Doctor is depicted as being emotionally closed off, hiding her grief from the Master's destruction of their home planet, Gallifrey, behind an energetic exterior. 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."The Woman Who Fell to Earth" (2018)"The Power of the Doctor" (2022) Fourteenth DoctorPhysically resembling the Tenth Doctor in appearance, the Fourteenth Doctor has a similar characterisation, though the Fourteenth Doctor has differences in his character due to the character growth experienced between the two incarnations. 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). After defeating the villainous Toymaker, the Fourteenth Doctor retires alongside his companion Donna Noble and her family while the Fifteenth Doctor continues exploring the universe."The Star Beast" (2023)"The Giggle" (2023) Fifteenth DoctorFollowing the battle against the Toymaker, the Fifteenth Doctor continues to explore the universe. He is characterised as being joyful and a flirt, engaging in a relationship with the character Rogue, while also fighting against a recurring Pantheon of Gods. The Fifteenth Doctor dies fighting the Time Lords the Rani and Omega, after which he regenerates into a form resembling that of Rose Tyler."The Giggle" (2023)"The Reality War" (2025)

Other incarnations + Incarnation Characteristics Main appearances Primary actor First LastDr. WhoThe incarnation of the Doctor featured in a pair of spin-off films released in the 1960s. Unlike the Doctor's usual depiction, Dr. Who is presented as a kind human who invented the TARDIS by himself. This incarnation, and the films he appears in, are not traditionally considered part of the main Doctor Who continuity.Dr. Who and the Daleks (1965)Daleks' Invasion Earth 2150 A.D. (1966)War DoctorAn incarnation of the Doctor who fought in a conflict known as the Time War. Retroactively introduced in the series' narrative, the War Doctor is placed between the Eighth and Ninth Doctors."The Name of the Doctor" (2013)"The Day of the Doctor" (2013)Fugitive DoctorA mysterious incarnation with an unclear placement in the Doctor's timeline. She is depicted as having a "darker" characterisation, and is willing to use weapons if necessary. "Fugitive of the Judoon" (2020)"The Story & the Engine" (2025)

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.

Susan Foreman Ian Chesterton Barbara Wright Vicki Steven Taylor Dodo Chaplet Ben and Polly Jamie McCrimmon Victoria Waterfield Brigadier Lethbridge-Stewart Zoe Heriot Liz Shaw Jo Grant Sarah Jane Smith Harry Sullivan Leela K9 Romana Adric Nyssa Tegan Jovanka Vislor Turlough Peri Brown Mel Bush Ace Bernice Summerfield Rose Tyler Adam Mitchell Jack Harkness Mickey Smith Donna Noble Martha Jones Wilfred Mott Amy Pond Rory Williams River Song Clara Oswald Nardole Bill Potts Graham O'Brien Ryan Sinclair Yasmin Khan Ruby Sunday Belinda Chandra

Antagonists During the Doctor's travels, a number of villains have been encountered, with many of them serving as antagonists. The Doctor and their companions often work to stop these villains from achieving various villainous schemes and plans.