Aliases of the Doctor

Throughout his travels in time and space, the Doctor took and was called by a number of different aliases, titles and names. Some were fleeting. Others, for example John Smith, were used by almost all of his incarnations. The Doctor told few individuals his real name. Instead, he asked others to call him the Doctor.

Ubiquity of the title
"The Doctor" was not a name, but a title. His true name was not generally known, and "the Doctor" became an alias. It has been implied his given name was ceremoniously withdrawn and stricken by his Cousins as punishment for a disgrace he visited upon his House. (PROSE: Lungbarrow)

The Doctor's real name has been said to be difficult to pronounce, for humans at least. He once told an interrogator (when asked his name), "You wouldn't be able to pronounce the first syllable of it." (PROSE: Salvation) Much later in his life, his seventh incarnation likewise told one of his captors, "I doubt you'd be able to pronounce the name I was originally given." (PROSE: Illegal Alien)

Even when he was twice put on trial by his own people, the Time Lords, he was only referred to as "the Doctor", (TV: The War Games) although the Valeyard, who prosecuted the second trial (and who himself was a culmination of the dark side of a future incarnation of the Doctor), acknowledged that it was an alias. (TV: The Trial of a Time Lord) However, as the Doctor chose that "name" as a Gallifreyan custom, (TV: The Sound of Drums) its use in an official capacity was not exceptional. The Doctor kept his true name hidden despite numerous "mind-probe" attempts, voluntary (TV: The Lodger) and involuntary. (TV: The Girl in the Fireplace, The Shakespeare Code)

Individuals with knowledge of his name
When the Tenth Doctor first encountered her, River Song claimed to have known him at some point in his future. She was one of the few individuals confirmed to know his true name. To win the Doctor's trust and prove her "credentials", she whispered his name in his ear, and apologised for having to do so. The Doctor seemed shocked at this, later saying to her, "There is only one reason I would ever tell anyone my name, only one time I could." (TV: Forest of the Dead)

When asked about the Sixth Doctor's name, his companion Peri Brown once said that the Doctor had told her she would find it unpronounceable. (AUDIO: Slipback)

The Sixth Doctor told Becky his name. (PROSE: Teach Yourself Ballroom Dancing)

The Eighth Doctor's companion Samantha Jones was told his real name. She found it quite alien and virtually unpronounceable. (PROSE: Unnatural History, Vanderdeken's Children)
 * When the Doctor spoke his real name aloud in the novel Vanderdeken's Children it was not written in the prose, but represented by "—" instead.

Near the end of his tenth incarnation, members of an unidentified pan-dimensional race came to know the Doctor's real name. At this point he was of the opinion there was no one left in the universe who knew it. (AUDIO: The Last Voyage)

Clara Oswald read his name in The History of the Time War. That timeline was later averted, however, leaving her with no memory of it. (TV: Journey to the Centre of the TARDIS)

True name
The Carrionite Lilith, unable to discover the Tenth Doctor's true name even with the "witchcraft" used by her kind, remarked, "There is no name. Why would a man hide his title in such despair?" (TV: The Shakespeare Code) The psychically-gifted Evelina, who attempted to foretell the Doctor's future, remarked that his "true name" was "hidden" from her. (TV: The Fires of Pompeii)

According to Dorium Maldovar after his beheading, the religious organisation the Silence had a particular interest in the Doctor's name. He explained that if the Doctor lived long enough, on the fields of Trenzalore, at the fall of the Eleventh, when no creature could speak falsely or fail to answer, a question that must never be answered would be asked: the first question, hidden in plain sight. The question was simply: "Doctor Who?". The Silence wanted to stop the Doctor from revealing his true name. (TV: The Wedding of River Song) The Doctor was at a later time forced to go to Trenzalore to rescue his friends from the Great Intelligence, which sought to gain access to the Doctor's tomb. The tomb, which was a future version of his own dying TARDIS, would open only to the Doctor's real name. The Intelligence threatened to kill the Doctor's friends if he did not speak his name and open the tomb; the situation was resolved when the data ghost of River Song was able to silently transmit his name to the TARDIS, thus opening the door for the Great Intelligence. (TV: The Name of the Doctor )

Eventually, the Doctor held a book called The History of the Time War in his TARDIS library, unfolding the history of the Last Great Time War and apparently containing his name. (TV: Journey to the Centre of the TARDIS)

Significance
The Eleventh Doctor told Clara Oswald that his real name was not important, since he specifically chose the title of "Doctor" to take its place, "like a promise you make." (TV: The Name of the Doctor) This promise was, as recited by the Tenth and War Doctors, "Never cruel or cowardly. Never give up, never give in." (TV: The Day of the Doctor)

knew of this and implied that the Doctor's title had been chosen because it meant "the man who makes people better", although he found the choice "sanctimonious" for someone who ended millions of lives and ruined many others. (TV: The Sound of Drums) River Song was aware of this contradiction in the Doctor's behaviour: she said that the Doctor was the first to have this title and that the rest of the universe later adopted it, usually to mean "healer" or "wise man"; however, she added, in some parts of the universe (eg. the Gamma Forests), it eventually came to mean "mighty warrior". (TV: A Good Man Goes to War)

The Doctor did possess at least one doctorate. (TV: The Moonbase, The Armageddon Factor, The Mysterious Planet) He sometimes described himself as a "doctor of many things" (TV: Four to Doomsday) or "everything". (TV: Spearhead from Space, Utopia) On several occasions the Doctor stated he was not a medical doctor. (TV: "The Forest of Fear", "Mighty Kublai Khan", AUDIO: Red Dawn) That didn't stop his second, third,  tenth and eleventh incarnations from sporting a stethoscope on occasion. (TV: The Runaway Bride, Partners in Crime, Planet of the Ood, Planet of the Dead, The Doctor's Daughter, The Lodger, etc) The Doctor did note that by his second incarnation, he had studied medicine in the 19th century. (TV: The Moonbase) He also claimed one of his doctorates was in cheese making. (TV: The God Complex)

The Doctor's real name became important during the Siege of Trenzalore, as it was the signal chosen by the Time Lords to come back to the universe. Despite this, Clara told them instead that the only name of his that mattered was "the Doctor", prompting them to give the Doctor a new regeneration cycle, and close the Crack they were using to reach out to the universe. (TV: The Time of the Doctor)

Common aliases
Numerous names, titles and epithets were either used by or bestowed upon the Time Lord most widely known as the Doctor.

The Doctor
As noted above, the Doctor itself was an alias, despite it being the title by which the Time Lord was most widely known. It was claimed that, as a Gallifreyan custom, he chose this alias himself. (TV: The Sound of Drums) On one occasion, a human knew this name without the Doctor saying it out loud. (PROSE: Cat's Cradle: Warhead) His other aliases often included the title "Doctor". (TV: Spearhead from Space) He implied to Peri his given name also began with such a title. (TV: The Mysterious Planet) Drax, a fellow Time Lord, indicated the Doctor did indeed possess a doctorate. (TV: The Armageddon Factor) According to one account, during his first incarnation, the Doctor adopted this name in dealing with human colonists on the planet Iwa at the same time that his granddaughter adopted the name "Susan". (PROSE: Frayed) According to another account, the Doctor and Susan already went by these names when they left Gallifrey. (AUDIO: The Beginning)

During his eleventh incarnation, the Doctor claimed that he didn't actually know why he and other people called him "the Doctor". (TV: The Lodger)

John Smith
John Smith was an alias the Doctor frequently used on Earth and around humans when a "standard" name was needed. It was often preceded by the title "Doctor", though not always — for example, when he was undercover as a teacher at a school or a patient in a hospital. (TV: School Reunion, Smith and Jones) During his first incarnation, he used a library card with the name Dr J. Smith while living at 76 Totter's Lane, (TV: The Vampires of Venice) as well as for identification when renting the junkyard. (PROSE: The Rag and Bone Man's Story) The inspiration for the alias was John Smith of John Smith and the Common Men, with which he was familiar through Susan. (PROSE: The Witch Hunters) In his second incarnation, the name was independently used by his companion Jamie McCrimmon (who would not have known of the Doctor's earlier use of the name) while the Doctor was being treated for concussion, as he saw it being used as a brand name on a metal container. (TV: The Wheel in Space) Later, the Doctor adopted it on a semi-regular basis during his third incarnation while exiled on Earth, when he served as unpaid scientific advisor to UNIT. (TV: Spearhead from Space, et al)

As "John Smith" was considered a generic name in some Earth cultures, the Doctor's use of the alias was occasionally treated with scepticism. (TV: Midnight)

The Doctor twice changed himself into a human who used the name John Smith. This occurred in his seventh incarnation (PROSE: Human Nature) and in his tenth. (TV: Human Nature/The Family of Blood)

Known uses of John Smith

 * The name was on the First Doctor's library card while he was living at 76 Totter's Lane. (TV: The Vampires of Venice)
 * He used it as identification when renting the junkyard from its owner, Hawkins. (PROSE: The Rag and Bone Man's Story)
 * He used it when Rebecca Nurse asked his name, realising that a simple "Doctor" would not do. (PROSE: The Witch Hunters)
 * He used it to check in at Ingersoll's tavern in Salem. (PROSE: The Witch Hunters)
 * It was given to him by Jamie and used aboard Space Station W3. (TV: The Wheel in Space)
 * He used it when questioned by a German soldier, who replied, "Good. Now we are getting somewhere." (TV: The War Games)
 * The Third Doctor used it during his exile on Earth with UNIT, when he served as its scientific advisor. (TV: Spearhead from Space, Inferno, The Time Warrior)
 * He used it on the planet Kastopheria when asked by Administrator Charteris, who responded with, "A large family, the Smiths." (PROSE: Catastrophea)
 * The Fifth Doctor used it on both the Confederate and Union sides of the American Civil War as a guise under which he could render medical assistance, while having the freedom to search for his lost companions, Peri and Erimem. He received some local publicity under the name after delivering the baby of the mayor of Gable, West Virginia. He was personally known to Abraham Lincoln by this name after he had saved the president's life during an assassination attempt in Richmond, Virginia. (PROSE: Blood and Hope)
 * "JSMITH" was the Sixth Doctor's username online (PROSE: Blue Box) and "Jsmith8" was the Eighth's. (PROSE: Lonely)
 * A German variation of this name, "Johann Schmidt," was used by the Sixth Doctor when he infiltrated the Third Reich to investigate the origins of the Fourth Reich that was currently active in 2001, creating fake credentials establishing him as Major-General Johann Schmidt of the Berlin Fifth Medical Corps. (PROSE: The Shadow in the Glass) The Seventh Doctor also used this name while impersonating the Reichsinspektor General, (PROSE: Timewyrm: Exodus) while the Eighth Doctor used it while posing as a German spy. (AUDIO: Storm Warning) An alternative version of the Eighth Doctor who existed in a timeline where the Nazis won World War II, also used the name. (AUDIO: Colditz, Klein's Story) The Eleventh Doctor took the place of a real Dr Schmidt when his psychic paper displayed the credentials of a visitor expected at the Lexington Bank. (PROSE: Borrowed Time)
 * A French variation, "Jean Forgeron," was used by the Fourth Doctor when met by French soldiers in the labyrinth underneath Paris. (COMIC: The Forgotten)
 * The name was given to him coincidentally by Chang Lee on his hospital admittance forms after he was shot near the end of his seventh incarnation. (TV: Doctor Who)
 * The name appeared as "Dr John Smith" on a piece of psychic paper during a visit to 1941 (although the Doctor never actually used the alias on this occasion). (TV: The Empty Child)
 * The Tenth Doctor used the name while working undercover as a science teacher at Deffry Vale High School. (TV: School Reunion)
 * He also used it while posing as a patient at Royal Hope Hospital (TV: Smith and Jones)
 * The Tenth Doctor told Professor Conrad Morris that his name was John Smith in 2088. (PROSE: The Story of Martha: Breathing Space)
 * The Tenth Doctor used the name while impersonating a health and safety officer during an investigation of Adipose Industries. (TV: Partners in Crime)
 * The Tenth Doctor attempted to use the alias aboard the Crusader 50 bus on the planet Midnight when asked for his name, but it was recognised as a false name and rejected by the panicking humans aboard. (TV: Midnight)
 * He used it when "reintroducing" himself to Donna Noble after he erased her memories of him. (TV: Journey's End)
 * He used it when encountering Jackson Lake, a man who, due to Infostamp exposure, believed himself to be an incarnation of the Doctor. (TV: The Next Doctor)
 * The Eleventh Doctor used it while posing as his Ganger counterpart as an independent name for himself. (TV: The Almost People)
 * While at Eddison Manor after the murder of Professor Gerald Peach, the Tenth Doctor claimed to be Chief Inspector Smith of Scotland Yard in order to keep the police out of what he suspected (correctly, as it turned out) to be an alien crime. (TV: The Unicorn and the Wasp)
 * The Doctor introduced himself as Dr Smith, and Clara as his wife, to Mrs Gillyflower to try and infiltrate Sweetville. (TV: The Crimson Horror)
 * The Twelfth Doctor introduced himself as Doctor John Smith to Michael Smith. (PROSE: Silhouette)
 * The Twelfth Doctor used the alias when going undercover as a caretaker in Coal Hill School. (TV: The Caretaker)

Theta Sigma
Theta Sigma (ΘΣ), informally Thete, was a nickname of the Doctor at the Time Lord Academy on Gallifrey. (TV: The Armageddon Factor, The Happiness Patrol, COMIC: Flashback)

When the Doctor's final incarnation died for good during the first battle of the War, his coffin — which came to be known as the Relic — had the symbols for "Theta" and "Sigma" on it (PROSE: Alien Bodies).

In an alternative timeline in which Rassilon failed to finish the Eye of Harmony before his death, the Doctor never left Gallifrey and became a commentator rather than a renegade Time Lord. He was known as Commentator Theta Sigma. (AUDIO: Forever)

Theta Sigma was part of River Song's message to the Doctor on the universe's oldest cliff-face. (TV: The Pandorica Opens)

Doctor Who
The name Doctor Who was applied to the Doctor, intentionally or unintentionally, on several occasions.


 * The computer WOTAN referred to the First Doctor as Doctor Who. (TV: The War Machines)
 * The Second Doctor briefly used the name Doktor von Wer (literally 'Doctor [of] Who') during his visit to Scotland on 16 April 1746.(TV: The Highlanders)
 * The Second Doctor once signed a message as "Dr W." (TV: The Underwater Menace)
 * K9 was heard on occasion making playful remarks related to the Who name. (TV: A Girl's Best Friend, Invasion of the Bane)
 * The Fourth Doctor wrote a series of children's books during his time with UNIT which were mistakenly published under this name. (AUDIO: The Kingmaker)

Other aliases
The following is a list of aliases used by the Doctor in each of his incarnations.

First Doctor

 * Doctor Foreman: Often addressed as such due to the assumption that he shared Susan's surname. (TV: An Unearthly Child) Officially used the alias during his trial for the killing of a werewolf. (PROSE: The Juror's Story)
 * Maximus Pettulian: While visiting the Roman Empire shortly before the Great Fire of Rome in July 64, the Doctor briefly impersonated a murdered lyre player named Maximus Pettulian in the court of Nero. (TV: The Romans)
 * Zeus: When the Greek warrior Achilles mistook the Doctor for Zeus posing as an old man in circa 1200 BC, he went along with it, until the unconvinced Agamemnon spoiled the Doctor's ruse. (TV: The Myth Makers)
 * Doctor Caligari: The Doctor used it when he arrived in Tombstone, Arizona in October 1881, impersonating a magician. However, the locals mistook him for Doc Holliday. (TV: The Gunfighters)
 * Benjamin Jackson: Used when he returned to the Salem Village.
 * Wissfornjarl: While on the Isle of Hoy, Orkney in 1956, the Doctor was given this name by the spaywife Janet McKay. After seeing his arrival in the TARDIS, she mistook him for the island's protector from Norse mythology. He believed that it was simplest to accept the name. The name meant "Wise Old Chieftain," which Ian thought was appropriate. (AUDIO: The Revenants)

Second Doctor

 * The Examiner: Still not sure if he was the Doctor after his first regeneration, the Doctor took on the identity of an Examiner from Earth after the original one was assassinated by Bragen. (TV: The Power of the Daleks) Near the end of his life, he masqueraded as another Examiner, this time of a non-existing War Prison in an attempt to liberate Jamie from said prison. (TV: The War Games)
 * Doctor Galloway: Edward Waterfield made up this name for the Second Doctor when arranging to meet him. (TV: The Evil of the Daleks)
 * Doctor Mason: An alias used when he took part in a jury at the trial of the First Doctor for killing a werewolf. (PROSE: The Juror's Story)
 * Dr. Rip Van Winkle: A name given to him by Mrs Craig. (PROSE: The Indestructible Man)
 * Gaius Iunius Faber: "Iunius Faber" being the Latin equivalent of John Smith. The Second Doctor used this alias during his visit to Bruttium, Italy in 71 BC. (PROSE: The Slave War)

Third Doctor

 * The Great Wizard, Qui Quae Quod: Miss Hawthorne referred to the Doctor as "the great wizard Quiquaequod" while attempting to bluff the villagers of Devil's End into releasing him. In Latin, qui, quae and quod are the masculine, feminine and neuter nominative forms of the relative pronoun "who" - literally, Miss Hawthorne was calling him "Who Who Who".(TV: The Dæmons)
 * Prisoner 177781: The Doctor was recorded by this designation when he was briefly arrested by the British Army alongside Sarah Jane Smith, who was recorded as Prisoner 177782. (TV: Invasion of the Dinosaurs)
 * The Master: Forced to masquerade as the Master when the latter switched bodies with him. (PROSE: The Switching)
 * Doctor Noble: An alias used when he took part in a jury at the trial of the First Doctor for killing a werewolf. (PROSE: The Juror's Story)

Fourth Doctor

 * Hieronymous: Stole Hieronymous's robes and pretended to be him to defeat the Mandragora Helix. (TV: The Masque of Mandragora)
 * Oskin: The Doctor masqueraded as Oskin in order to destroy The Asteroid. (AUDIO: Requiem for the Rocket Men)
 * ?: The Doctor signed a document with a question mark prior to the Sontaran invasion of Gallifrey. (TV: The Invasion of Time)

Fifth Doctor

 * The Supremo: The Doctor called himself "the Supremo" while leading the alliance against the army of the renegade Time Lord Morbius. Originally, his title was "Supreme Controller", but the Ogrons of his personal guard could not pronounce it and shortened it to the simpler "Supremo". (PROSE: Warmonger)
 * Dr Jonas Smythe: The Doctor used this name when working with Liz Shaw in Italy. (PROSE: Flashpoint)
 * Doctor Walters: The Doctor used this name while stuck in Victorian London without his TARDIS for a year from November 1866 - 1867. (AUDIO: The Haunting of Thomas Brewster)

Sixth Doctor

 * Doktor of TARDIS: Used by the Sixth Doctor to move discreetly around an alternate version of the city of Rome. (PROSE: State of Change)
 * Albert Einstein: Used by the Doctor while meeting with Charles Darwin in the Galapagos Islands in 1835. (AUDIO: Bloodtide)
 * Banto Zame: Posed as Zame when the latter's impersonation of the Doctor landed him in trouble. (AUDIO: The One Doctor)
 * The Sandman: Adopted as part of a plan to stop an alien race attacking others by inspiring the idea of him as a monster. (AUDIO: The Sandman)
 * Zarl: After the Doctor had chased him to his death, the Doctor impersonated Zarl to maintain the web of time and his previous incarnation's meeting with Zarl. (AUDIO: Peri and the Piscon Paradox)
 * Claudius Dark: Used while the Doctor was undercover in the 19th century, so as to avoid the attention of Mr Kempston and Mr Hardwick. (AUDIO: The Hourglass Killers)
 * Dr Grigori Kalashnikov: The Doctor adopted the identity of a Moscow University scientist when he arrived at the Baikonur Cosmodrome in Kazakhstan on 10 November 1963. (AUDIO: 1963: The Space Race)

Seventh Doctor

 * ?: The Doctor signed a document with a question mark during a visit to London in 1963. (TV: Remembrance of the Daleks)
 * Merlin: The Doctor was mistaken by the people from an alternate universe which inspired the Arthurian legend to be Merlin, (TV: Battlefield) due to the Eighth Doctor using the alias when delivering King Arthur. (PROSE: One Fateful Knight)
 * John Doe: The customary name in America for an unidentified human male was applied to the apparently dead Doctor by the staff of Walker General Hospital, and he was given a "John Doe" toe tag before being wheeled into the morgue's freezer, where he subsequently regenerated into his eighth incarnation. (TV: Doctor Who)
 * Commander John Ballard: The Doctor was mistaken for the new commander of Dark Space 8 after he and Melanie Bush were teleported aboard the station following the destruction of Ballard's shuttle. (AUDIO: Bang-Bang-A-Boom!)
 * Mr. Ashcroft: The Doctor used this name to acquire recordings from Bianca's. (AUDIO: The Wormery)
 * Richard A. Fells: The Doctor used this name while posing as a prisoner in Alcatraz. (PROSE: Inmate 280)
 * Dr Vaughn Sutton: Used on Perfugium, (AUDIO: Master) based on an alias used by Lord Grayvorn. (AUDIO: Excelis Decays)
 * John Rutherford: Using this pseudonym, the Doctor was elected as an independent member of Parliament in May 1963 on a platform of nuclear disarmament. (AUDIO: The Assassination Games)

Eighth Doctor

 * Dr James Alistair Bowman: Dr. Grace Holloway came up with the name "Dr Bowman" for the Eighth Doctor whilst introducing him to others at the New Year's Eve party. (TV: Doctor Who) The Doctor subsequently used this alias on occasion, filling it out to James Alistair Bowman. (PROSE: Seeing I)
 * The Eighth Man Bound: The Doctor referred to himself as this name, based on the fact that the Doctor was the only student to see a glimpse of his future right up to his eighth incarnation in the Eighth Man Bound game. (PROSE: Christmas on a Rational Planet, Lungbarrow, The Dying Days)
 * Gracie Witherspoon: To defeat the Threshold, the Doctor used a personal chameleon circuit to take the appearance of a female Threshold agent while Shayde masqueraded as the Doctor. (COMIC: Wormwood)
 * The Bringer of Darkness, the Oncoming Storm and the Evergreen Man: all epithets he offered Slake. He also gave his full, former Time Lord title as President of the High Council of the Time Lords, Keeper of the Legacy of Rassilon, Defender of the Laws of Time and Protector of Gallifrey. (PROSE: Vampire Science)
 * Dr Jack-of-the-Moon: This was a term meaning those who concentrated on high-minded things at the expense of the normal world. It was used to refer to the Doctor (for example, on his marriage invitation) during his time on Henrietta Street. (PROSE: The Adventuress of Henrietta Street)
 * Merlin: Whilst stuck in the otherworld of Avalon, the Doctor attempted to pass himself off as Merlin to Queen Mab. (PROSE: The Shadows of Avalon) He later took up the alias again to deliver King Arthur in another reality. (PROSE: One Fateful Knight)
 * Dr Friedlander: While visiting Banquo Manor, he assumed the name of a real Doctor Friedlander who hadn't arrived at the Manor in order to avoid having to explain his presence. (PROSE: The Banquo Legacy)
 * Dr Domecq: When impersonating a representative of Earth Central. (PROSE: Dark Progeny)
 * Sir Doctor Peter Pollard: When he arrived at Sebastian Grayle's 19th centuary manor house, with Charlotte Pollard pretending to be his daughter. (AUDIO: Seasons of Fear)
 * Perdix: While in Rhadamanthys' court. (PROSE: Fallen Gods)
 * Bert Higgins: While on Nixyce VII. (AUDIO: The Traitor, Eyes of the Master)

War Doctor

 * The Warrior: The persona the Doctor chose to take in the Fifth Segment of the Time War upon regenerating out of his dying eighth incarnation by using the Elixir of Life. By the time he went back to the First Segment of the war, he had gone by this name for a considerable amount of time, but it is unclear if he had stopped doing so by then. (TV: The Night of the Doctor, PROSE: The Stranger) Clara Oswald later referred to him as "the Warrior" as well. (TV: The Day of the Doctor)

Ninth Doctor

 * Mr Spock: Rose Tyler, annoyed with the Doctor not telling her his name, introduced him to Captain Jack as Mr. Spock. (TV: The Empty Child)
 * Hal Gryden: While on the planet Arkannis Major, the Doctor adopted the name of this fictional newscaster to broadcast a message of peace to the people of the world. (PROSE: The Stealers of Dreams)
 * Brigadier Bambera: Used when visiting the Christmas truce of World War I. (COMIC: The Forgotten)
 * Doctor Table: Used while trying to get a Neanderthal out of a hospital, claiming to be an expert in a rare disease that the man was suffering from (PROSE: Only Human).
 * Inspector George Dixon: Used when helping the police department on 23rd century New Vegas with their investigation into the Whisper. (AUDIO: Night of the Whisper)

Tenth Doctor

 * Doctor James McCrimmon: The Tenth Doctor briefly called himself Dr. James McCrimmon while visiting Scotland in 1879; this was the name of one of his old companions. Later, he dropped the alias and was knighted by Queen Victoria as "Sir Doctor of TARDIS". (TV: Tooth and Claw)
 * Sir Doctor of TARDIS: After being knighted under this name, the Doctor tried to use it when he met William Shakespeare. Shakespeare's mind could not be swayed by psychic paper used to show his title. (TV: The Shakespeare Code)
 * Doctor Vile: The Doctor briefly masqueraded as the space pirate Doctor Vile to stop a war between humans and intelligent insects. (TV: The Infinite Quest)
 * Doctor McCoy: After a discussion with Donna Noble, in which she compared the sonic screwdriver to Star Trek's, the Doctor used the alias Dr McCoy (after Dr. ) when dealing with a group of soldiers (Donna called herself Captain Kirk, after ). (AUDIO: Pest Control)
 * Spartacus: When visiting Pompeii in 79 A.D, the Doctor and Donna both called themselves 'Spartacus', which had been a minor joke. (TV: The Fires of Pompeii)
 * Chief Inspector Smith from Scotland Yard: Used when involved with the death of Professor Peach. (TV: The Unicorn and the Wasp)
 * Doctor Noble: The Doctor used this when investigating the Ood Industries claiming that he and Donna were from the Noble Corporation. (TV: Planet of the Ood)
 * Actors: When visiting Hollywood in the early 20th century, the Doctor adopted a number of Hollywood-related names whilst attending a party. Within the space of a few minutes, he called himself "Tom Cruise", "Michael Caine", "Pee-Wee Herman" and "Tom Hanks". (COMIC: Silver Scream)
 * Bringer of Darkness: While facing a rabbit, which he thought was a Zygon. (TV: The Day of the Doctor)

Eleventh Doctor

 * Captain Troy Handsome of International Rescue: When introducing himself to a crashed time ship's avatar. (TV: The Lodger)
 * Commander Bond of Naval Intelligence: An alias used by the Doctor when he encountered Gein. (COMIC: Sub-species)
 * The Anti-Squid: A title the Doctor put little thought into due to the lack of preparation time. Meaning of the title is that he is the Devil of the space squid religion. (PROSE: Space Squid)
 * Fred Astaire: An alias he used when asked to sign his name for a magic show audition. (PROSE: Magic of the Angels)
 * The Caretaker: Alias used when Madge, Lily and Cyril Arwell stayed with him in a dilapidated house in Dorset. (TV: The Doctor, the Widow and the Wardrobe)
 * Jean Valjean: Alias used by the Doctor to infiltrate Alcatraz as a prisoner; he based on it on a musical years in the future. (COMIC: Escape into Alcatraz)
 * Sherlock Holmes: used to gain entry to Dr Simeon's institute. Strax even called the Doctor this a few times just to annoy him. (TV: The Snowmen)
 * Proconsul: Alias used during his adventure at Hedgewick's World of Wonders to keep a punishment platoon from being hostile to him and his guests. (TV: Nightmare in Silver)
 * Chief Executive: Alias used by the Doctor under the influence of the Entity. (COMIC: The Rise and Fall, The Other Doctor, Wishing for Wishes)

Twelfth Doctor

 * Prisoner 428: His assumed title during his time in the Prison. (PROSE: The Blood Cell)
 * The Architect: A title used to disguise his identity when arranging to rob the Bank of Karabraxos; until the heist was almost complete, he was unable to remember this thanks to the deliberate use of a memory worm. (TV: Time Heist)
 * Dr. McGuiness: An alias he assumed while investigating "the Bell" experiment in 1944, but was quickly found out and mistaken for a German spy. (PROSE: The Crawling Terror)

Nicknames
A list of names other individuals have called the Doctor throughout his travels.

First Doctor

 * The Traveller from Beyond Time: The epiphet given to the Doctor by the Elders. (TV: The Savages)
 * Pops: General Cutler disrespectfully called the Doctor this due to his old age. (TV: The Tenth Planet)
 * Snail / Wormhole: Given to him by his cousins of the House of Lungbarrow, because, unlike Loomed Gallifreyans, he had a bellybutton. (PROSE: Lungbarrow)

Second Doctor

 * Clown / Comedian: Nicknames bestowed upon him by the First Doctor (TV: The Three Doctors) and the Master (GAME: Destiny of the Doctors) for his comical personality and dress sense.
 * Ka Faraq Gatri: As early as his second incarnation, the Doctor knew that the Daleks had given him this epithet, and the Daleks used it prior to the destruction of Skaro. It translated as Destroyer of Worlds. (COMIC: Bringer of Darkness)
 * Scarecrow: Spitefully used as a retort against his unkempt appearance by the Third Doctor in return for being called "fancy pants". (TV: The Five Doctors)
 * The Comedian: Title given to the Second Doctor by the Master. (GAME: Destiny of the Doctors)

Third Doctor

 * Dandy: A nickname bestowed upon him by the First Doctor for his upper-class attire. (TV: The Three Doctors)
 * Fancy Pants: An insult used by the Second Doctor to get a parting shot in at his successor's appearance before the incarnations went their separate ways. (TV: The Five Doctors)

Fourth Doctor

 * The Evil One: The Sevateem tribe referred to the Doctor as "the Evil One." Xoanon, the supercomputer which they worshiped, had two personalities, one of which was based on the Fourth Doctor. (TV: The Face of Evil)
 * The Wizard: Emily, a child in whom Leela was reborn after her death, referred to the Doctor as "the Wizard." (AUDIO: The Child)
 * Master: K9's affectionate nickname for the Doctor. (TV: The Invisible Enemy, et al.)
 * The Watcher: To refer to a projection of the Doctor partway between his fourth and fifth incarnations, before they realised his true identity. The only individual heard to utter it was Adric. (TV: Logopolis)
 * The Bohemian / The Wanderer: Titles given to the Fourth Doctor by the Master. (GAME: Destiny of the Doctors)

Fifth Doctor

 * Demon: Called so by Kamelion, while the android was disguised as King John of England.

Sixth Doctor

 * Old One: Given by Balazar while investigating Ravolox. The Doctor took offense, as by Gallifreyan terms, he was actually still quite young. (TV: The Mysterious Planet)
 * The Dark One / He Whose Name Dare Not Be Mentioned: Names given to the Sixth Doctor/the Valeyard in the legends of the Great Kingdom, an unstable alternate version of London created by the botched summoning of Saraquazel. (PROSE: Millennial Rites)

Seventh Doctor

 * Professor: This was what Ace called the Doctor. (TV: Dragonfire, et al)
 * The Scottish Doctor: When Honoré Lechasseur once met the Doctor, he described him as such, as well as sporting a beard. (PROSE: The Cabinet of Light)
 * The Oncoming Storm was also the epithet given to him by the Draconians, ("Karshtakavaar" in Draconian) who were generally the Doctor's allies, to indicate the traumatic events which so often accompanied his arrival. (PROSE: Love and War)
 * Time's Champion: A title given to the Doctor for his service to Time during his seventh incarnation. (PROSE: Love and War)
 * Ka Faraq Gatri (other Dalek names): The Daleks referred to the Doctor as the Ka Faraq Gatri, which may mean Bringer of Darkness and/or Destroyer of Worlds or The Oncoming Storm. By implication, the epithet Destroyer of Worlds referred to the Doctor's destruction of the Dalek home planet Skaro in his seventh incarnation, an act for which he would feel some remorse. (PROSE:  Remembrance of the Daleks, PROSE: Timewyrm: Revelation, AUDIO: The One Doctor)
 * The Umbrella Man: After he rewrote her history, Elizabeth Klein referred to him as such given she was not aware of his identity. (AUDIO: UNIT: Dominion)

Eighth Doctor

 * Evergreen Man: The name given to him by the Sidhe. (PROSE: Autumn Mist)
 * Skipper: The Doctor's companion Samson Griffin always referred to him as such. (AUDIO: Terror Firma)
 * Tigger, Eeyore: When the Doctor is split into three, each bearing different parts of his personality, Charley Pollard gives these nicknames to the bouncy and excitable, and the surly and ruthless Doctors. (AUDIO: Caerdroia)

War Doctor

 * Grandad: A nickname given by the Eleventh Doctor due to the War Doctor's aged appearance. (TV : The Day of the Doctor)
 * Captain Grumpy: A nickname given by the Eleventh Doctor due to the War Doctor's serious personality. (TV: The Time of the Doctor)
 * The Mad Fool: A nickname given by the General, since the War Doctor was working against the Time Lords' plans and seemingly ensuring their destruction. (TV: The Day of the Doctor)
 * The Renegade: A name the Time Lords used to refer to the War Doctor as he planned to use the Moment to end the Last Great Time War. (COMIC: Sky Jacks)
 * Dalek-killer: a name awarded to the War Doctor by the Daleks. (PROSE: Engines of War)
 * The Great Scourge: a name awarded to the War Doctor by the Daleks. (PROSE: Engines of War)
 * The Living Death: a name awarded to the War Doctor by the Daleks. (PROSE: Engines of War)
 * The Executioner: a name awarded to the War Doctor by the Daleks. (PROSE: Engines of War)
 * Predator: a name awarded to the War Doctor by the Daleks. (PROSE: Engines of War) It would be used again with the Eleventh Doctor.

Ninth Doctor

 * The Great Exterminator: The name given to the Doctor by the Dalek Emperor whilst preparing a Delta Wave. (TV: The Parting of the Ways)
 * The Navvie: Honoré Lechasseur's nickname for the Doctor, due to his leather jacket. (PROSE: The Albino's Dancer)

Tenth Doctor

 * Merlin: The Tenth Doctor would later claim that he was called Merlin by King Arthur. (COMIC: Fugitive)
 * The Oncoming Storm: Rose Tyler called the Doctor by this name when she and Mickey Smith were captured by the Clockwork Droids and being prepared for dissection and was threatening them using that title. (TV: The Girl in the Fireplace ) When he was interrogating a Dalek aboard of the Wayfarer the Doctor used this title to introduce himself to the Dalek. (PROSE: Prisoner of the Daleks)
 * Martian Boy: Donna Noble often called the Doctor by this name if not using Spaceman, originally earning her protests that he was not from Mars, leading to her calling him the latter. (TV: The Runaway Bride etc.)
 * Spaceman: Donna Noble often called the Doctor by this name and Christina de Souza also referred to the Tenth Doctor by this as well. (TV: The Fires of Pompeii, Planet of the Dead)
 * Sweetie, Pretty Boy: Used by River Song the first time he meets her from his point of view. (TV: Silence in the Library / Forest of the Dead)
 * The Destroyer of Worlds: The Tenth Doctor was called this by Davros whilst destroying the New Dalek Empire; this declaration seemed to truly affect the Doctor as his expression changed drastically after hearing it. (TV: Journey's End)
 * Matchstick Man: A nickname given to him by his successor upon noticing he was exceptionally thin. (TV: The Day of the Doctor)
 * Sandshoes: Another mocking nickname given to him by the Eleventh Doctor in reference to his choice of footwear. (TV: The Day of the Doctor)
 * Dick van Dyke: Yet another mocking nickname given by the Eleventh Doctor, after the Tenth commented on the War Doctor's persona. (TV: The Day of the Doctor)
 * Hero: The word Clara Oswald used to best describe what kind of person the Tenth Doctor was trying to be like. (TV: The Day of the Doctor)

Eleventh Doctor

 * The Raggedy Doctor: (also, Raggedy Man) A nickname given to the Eleventh Doctor by Amy Pond, due to wearing the tattered remains of his predecessor's outfit. Amy told other people in Leadworth and they referred to him in this way when they met him. (TV: The Eleventh Hour) Amy would call him that just before she was permanently sent to the past by a Weeping Angel. (TV: The Angels Take Manhattan) As he was about to regenerate, the Doctor hallucinated Amy telling him affectionately "Raggedy Man - good night". (TV: The Time of the Doctor)
 * A Madman with a Box: A title Amy Pond bestows on him on their first encounter after 14 years, which he later adopts. (TV: The Eleventh Hour)
 * The Eleventh Doctor is quite often referred to as "a Madman" in general by many characters.
 * Gandalf/Space Gandalf: When questioned by Amy as to what he's like, the Doctor answers that he's this. His further explanation showed he had confused Gandalf with Yoda. (TV: Meanwhile in the TARDIS 2)
 * The Rotmeister: When he is talking to Craig Owens about the suspiciously growing rot on his ceiling, he refers to himself as the "Rotmeister" since he was an expert in rot. "Call me the Rotmeister," he says, No, actually, don't call me that, call me the Doctor." (TV: The Lodger)
 * The Oncoming Storm: The Doctor called himself this when he misinterpreted one of Craig's football mates asking for help in "annihilating" another team. (TV: The Lodger) He later referred to himself as this when the Daleks forgot him. (TV: Asylum of the Daleks)
 * Caesar: A Roman Auton, under the influence of River Song's hallucinogenic lipstick, in 102 A.D., mistook the Doctor for Caesar. (TV: The Pandorica Opens)
 * The King of Okay: A title he gave to himself when Amy was shocked to see him alive and well, having seen his older self be shot and killed at Lake Silencio. He immediately tossed the idea aside, saying it was a "rubbish title", giving Rory his own title instead. (TV: The Impossible Astronaut)
 * Sweetie: Frequently used by River Song as a dual greeting and affectionate nickname.
 * My Thief, My Beautiful Idiot: Names given to the Doctor by the spirit of his TARDIS during their brief time together when House took over the empty shell. (TV: The Doctor's Wife)
 * Time Boy: Used by Mels, the second incarnation of River Song, as she anticipated meeting the Doctor while growing up with her parents in Leadworth. (TV: Let's Kill Hitler)
 * Belot'ssar: Though it is not said to be specific to the Eleventh Doctor, it was used by the Ice Warriors to refer to him. The name means 'cold blue star' in reference to either the light on top of the TARDIS or the cold blue star he showed them to settle near after Mars became uninhabitable. The name was given to him by Lord Azylax. (PROSE: The Silent Stars Go By)
 * Predator of the Daleks: Whilst not specific to the Eleventh Doctor, (PROSE: Engines of War) it was used as a designation by the Daleks. (TV: Asylum of the Daleks)
 * Chin-Boy: Oswin Oswald calls the Eleventh Doctor this when encountering him on the Dalek asylum. (TV: Asylum of the Daleks)
 * The Mad Monk: Called this by the public in 1207 Cumbria, although it was noted that he was "definitely not a Monk." (TV: The Bells of Saint John)
 * Also Not Mum: Called this by Alfie Owens in 2011. (TV: Closing Time)
 * Monster: Ada Gillyflower called the Doctor her "monster", after he had been rejected by Mr Sweet's poison. She kept him alive because it was strange that he survived despite "rejection", and to have her own secret. (TV: The Crimson Horror)
 * Proconsul: Title assumed during his adventure at Hedgewick's World of Wonders to keep a Punishment Platoon from being hostile to him and his guests. (TV: Nightmare in Silver)
 * Clara's Boyfriend: Called this by Angie Maitland when she discovered Clara and the Doctor were time travellers (TV: The Crimson Horror) and upon leaving the TARDIS. (TV: Nightmare in Silver) He would later pose as Clara's Swedish boyfriend to her family. (TV: The Time of the Doctor) Shortly after regenerating, the Twelfth Doctor clarified that he was not really Clara's boyfriend, though he added that "it wasn't [her] mistake." (TV: Deep Breath)
 * Chinny: The Tenth Doctor's nickname for the Eleventh Doctor, who had a very prominent chin. (TV: The Day of the Doctor)

Twelfth Doctor

 * Boney Rascal: A nickname given to him by Robin Hood, due to the Doctor's slim and aged appearance. (TV: Robot of Sherwood)
 * The Stranger: Dubbed as such in one of Alan-a-Dale's ballads. (TV: Robot of Sherwood)
 * Outer Space Dad: Called so by Danny after he learned about the Doctor's identity; at the time, he had mistaken the Doctor for Clara's father. (TV: The Caretaker)
 * Mr. President: Called this during Death in Heaven by Kate Stewart and Missy. Due the massive scale Cyberman invasion Missy orchestrated, the Doctor was made president of Earth for the crisis.
 * Skeleton Man: A name given to him by Shona McCullough, who had mistaken him for a ghost when they first met. (TV: Last Christmas)
 * Magician: Another name given to the Doctor by Shona, who was critizing his attire since it didn't match the appearance of a scientist. (TV: Last Christmas) He was addressed as a magician by Bors as well. (TV: The Doctor's Meditation)
 * Ancient One: Referred to as such by the Skinks. (COMIC: Hyperballad)
 * The Eyebrows: A nicknamed given to him by to differentiate the twelfth incarnation from the other Doctors. (TV: The Witch's Familiar)

Other

 * The Oncoming Storm: The Daleks referred to the Doctor as the Oncoming Storm in "the ancient legends of the Dalek homeworld", as noted by his ninth incarnation, indicating that the Daleks feared him. (TV: The Parting of the Ways)
 * The Valeyard: A version of the Doctor created sometime between his twelfth and final incarnations. (TV: The Ultimate Foe)
 * Time Lord Victorious: The Tenth Doctor took on this title when he tried to break the laws of time to his own needs. (TV: The Waters of Mars)
 * The Beast: A name used in reference to the Doctor by the Great Intelligence. (TV: The Name of the Doctor)

Behind the scenes

 * The first edition of the behind-the-scenes book The Making of Doctor Who, published in 1972, stated that the Doctor's name was "δ³Σx²". This has never been confirmed in any Doctor Who narrative, but these letters do appear on the plinth in the Tomb of Rassilon in The Five Doctors. They are also seen on K9's regeneration unit in Regeneration.
 * During Comic-Con 2012, Steven Moffat, the head writer, has confirmed that he knows what the Doctor's real name is, although the said name has not, as of yet, appeared in-narrative.
 * In The Night of the Doctor, the incarnation of the Doctor that follows the Eighth Doctor is referred to in the closing credits by the name "War Doctor." This name has yet to actually be used on screen in a canonical setting; it was, however, used by Strax in a fourth wall-breaking lead-in for Deep Breath detailing all the Doctor's previous incarnations. In an interview with the Daily Mail published on 16 November 2013, actor John Hurt used the name to refer to his version of the Doctor.
 * Executive producer Steven Moffat jokingly said that no one can know the Doctor's name, except each successive showrunner. "We're commanded never to reveal what we have learned, because then the show would have to be renamed Mildred. Oh, bugger."