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.

The Doctor's real name
As his true name was not generally known, "the Doctor" became an alias. It was implied that his given name was ceremoniously withdrawn and stricken by his Cousins as punishment for a disgrace he brought upon his House. (PROSE: Lungbarrow)

Even when he was put on trial by the Time Lords, he was only referred to as "the Doctor", (TV: The War Games) although the Valeyard, a culmination of the Doctor's darker side who prosecuted the second trial, acknowledged that it was an alias. (TV: The Mysterious Planet) Even those who had known him in childhood addressed him only as "the Doctor," such as the Master, (TV: Death in Heaven) and the Rani. (COMIC: Weapons of Past Destruction)

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) Another account implied that the Doctor's title had been chosen as a Gallifreyan custom, (TV: The Sound of Drums) and that he had been using it before he left Gallifrey. (TV: The Name of the Doctor)

The Doctor's real name has been said to be difficult to pronounce, for humans at least, (AUDIO: Slipback) possessing thirty eight syllables. (PROSE: Sleepy) The First Doctor once told an interrogator he "wouldn't be able to pronounce the first syllable of [his name]." (PROSE: Salvation) His seventh incarnation likewise told one of his captors that he "doubt[ed] [they]'d be able to pronounce the name [he] was originally given." (PROSE: Illegal Alien) When asked about the Doctor's name, Peri Brown once said that the Doctor had told her she would find it unpronounceable. (AUDIO: Slipback)

The Doctor kept his true name hidden despite numerous "mind-probe" and truth field attempts. (TV: The Girl in the Fireplace, The Lodger, The Time of the Doctor) 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," and that the Doctor was hiding his true name in 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)

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, saying it was "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, such as in the Gamma Forests, it eventually came to mean "mighty warrior". (TV: A Good Man Goes to War)

According to Dorium Maldovar, 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: "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)

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)

Ubiquity of the title
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 of "everything". (TV: Spearhead from Space, Utopia, COMIC: The Cruel Sea) His eleventh incarnation claimed that one of his doctorates was in cheese making (TV: The God Complex) but only the "stinky, blue kind". (PROSE: Shroud of Sorrow)

On several occasions, the Doctor stated he was not a medical doctor, (TV: "The Forest of Fear", "Mighty Kublai Khan") though did note that, by his second incarnation, he had studied medicine in the 19th century. (TV: The Moonbase)

Individuals with knowledge of his name
Susan Foreman knew the Doctor's real name, and wrote it on the wrappings of a hypercube she sent to him after she had settled down on Earth. (PROSE: Ghost of Christmas Past)

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

The Eighth Doctor's companion, Samantha Jones, overheard his real name being said. She found it quite alien and virtually unpronounceable. (PROSE: Vanderdeken's Children)

When the Tenth Doctor first encountered her, River Song claimed to have known him at some point in his future, (TV: Silence in the Library) and, to prove her "credentials", she whispered his name in his ear, and apologised for having to do so. The Doctor was shocked at this, as "there [was] only one reason [he] would ever tell anyone [his] name, [and] only one time [he] could." (TV: Forest of the Dead) The fact River knew the name was confirmed when her data ghost used it to unlock the TARDIS on Trenzalore (TV: The Name of the Doctor). Prior to this, River indicated to Clara Oswald that she "made" the Doctor tell her his name and that "it took a lot of effort". At the time of their wedding, the Eleventh Doctor pretended that he was about to tell River his name, but did not ultimately do so at that moment. (TV: The Wedding of River Song)

Near the end of his tenth incarnation, despite believing there was no one left in the universe who knew it, the Doctor encountered members of an unidentified pan-dimensional race that knew his real name. (AUDIO: The Last Voyage)

While separated from the Eleventh Doctor, 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) though she later began to recall certain moments of the timeline, (TV: The Name of the Doctor) and claimed to know the Doctor's name when bluffing to the Cybermen about being the Doctor. (TV: Death in Heaven)

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

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 & 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 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) Likewise, Chang Lee chose to register the name for the Seventh Doctor while he was en route to get his bullet wounds healed. (TV: Doctor Who)

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, Inferno, The Time Warrior)

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 incarnation. (TV: Human Nature)

First Doctor

 * 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 & 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)

Second Doctor

 * 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)
 * He used it on the planet Kastopheria when asked by Administrator Charteris, who responded with, "A large family, the Smiths." (PROSE: Catastrophea)

Third Doctor

 * The Third Doctor regularly called himself "John Smith" when working as UNIT's scientific adviser. (TV: Spearhead from Space, The Time Warrior)

Fourth Doctor

 * A French variation, "Jean Forgeron," was used by the Fourth Doctor when met by French soldiers in the labyrinth underneath Paris. (COMIC: The Forgotten)

Fifth Doctor

 * 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)

Sixth Doctor

 * "jsmith" was the Sixth Doctor's username online. (PROSE: Blue Box)
 * The Sixth Doctor used the name while working in Hut 12A at Bletchley Park in 1944. (AUDIO: Criss-Cross)
 * He also used the name to infiltrate the Dominus Institute in 2016. (AUDIO: Vampire of the Mind)

Seventh Doctor

 * The Seventh Doctor was known as "the Infamous General Smith" by the Sontarans. (PROSE: Shakedown)

Eighth Doctor

 * "Jsmith8" was the Eighth Doctor's username online. (PROSE: Lonely)

War Doctor

 * The War Doctor used the name when introducing himself to Coyne, as he did not wish for his Time Lord heritage to be discovered. (PROSE: Engines of War)
 * He also used it to introduce himself to Garv on Keska. (AUDIO: The Thousand Worlds)

Ninth Doctor

 * The name appeared as "Dr John Smith" on a piece of psychic paper during the Ninth Doctor's visit to 1941. (TV: The Empty Child)

Tenth Doctor

 * 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)
 * 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 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 Tenth Doctor used the alias while pretending to be a manager of the Brainy Crisps industry. (PROSE: Code of the Krillitanes)
 * The Tenth Doctor introduced himself as John Smith to Cleo. (COMIC: The Fountains of Forever)

Eleventh Doctor

 * The Eleventh Doctor used it while posing as his Ganger counterpart as an independent name for himself. (TV: The Almost People)
 * The Doctor introduced himself as Dr Smith, and Clara as his wife, to Mrs Gillyflower to try and infiltrate Sweetville in 1893. (TV: The Crimson Horror)

Twelfth Doctor

 * 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)

Johann Schmidt
A German variation of "John Smith", "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)

The Twelfth Doctor used the name to gain Field Marshall Rommel's trust when he landed in the Sahara Desert during World War II. (COMIC: The Instruments of War)

Theta Sigma
Theta Sigma, informally Thete and occasionally spelt "ΘΣ", was a nickname of the Doctor at the Time Lord Academy on Gallifrey. (TV: The Armageddon Factor, The Happiness Patrol; COMIC: Flashback) It identified him uniquely amongst the Time Lords and was not to be spoken outside of the Academy. (PROSE: Falls the Shadow)

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)

Oncoming Storm
The Doctor was referred to as the "Oncoming Storm" by the Draconians, (PROSE: Love and War) and in in "the ancient legends of the Dalek homeworld". (TV: The Parting of the Ways) In Draconian, the title was pronounced "Karshtakavaar". (PROSE: Love and War) After being told of the title by the Ninth Doctor, (TV: The Parting of the Ways) Rose Tyler called the Tenth Doctor by the "Oncoming Storm" when she and Mickey Smith were being prepared for dissection by the Clockwork Droids. (TV: The Girl in the Fireplace)

The Tenth Doctor later introduced himself as the "Oncoming Storm" to a Dalek aboard of the Wayfarer, (PROSE: Prisoner of the Daleks) and referred to the title when confronting a rabbit he thought was a Zygon. (TV: The Day of the Doctor)

The Eleventh Doctor began calling himself the "Oncoming Storm" when he misinterpreted Shaun request to help the Kings Arms football team "annihilate" another team at a match. (TV: The Lodger) He later referred to the title when the Daleks forgot him. (TV: Asylum of the Daleks)

As early as his second incarnation, the Doctor knew that the Daleks had also given him the epithet "Ka Faraq Gatri", (COMIC: Bringer of Darkness) which translated as "Destroyer of Worlds". (PROSE: Timewyrm: Revelation) He had been awarded the name upon orchestrating the destruction of the Dalek home planet Skaro in his seventh incarnation, (TV: Remembrance of the Daleks) though the Daleks also used it prior to Skaro's destruction. (COMIC: Bringer of Darkness) Davros also referred to the Doctor as "the Destroyer of Worlds" after the Meta-Crisis Tenth Doctor destroyed the New Dalek Empire on the Crucible. (TV: Journey's End)

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

First Doctor

 * Dr. Earl 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) and later added the forename Earl. (PROSE: The Duke's Folly)
 * 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. (PROSE: The Witch Hunters)
 * 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)
 * 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)
 * Albert Einstein: Used by the Doctor while meeting with Charles Darwin in the Galapagos Islands in 1835. (AUDIO: Bloodtide)
 * 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)
 * Nico Blair: Briefly used when trying to convince Carburetor that the Piscons were part of a television prank. Nico Blair was supposedly an expert on alien special effects. (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)
 * Mr. Nocturne: Used when he arrived a few days early after receiving a message from Jago and Litfoot. In order to preserve time, he couldn't let them meet him before they sent the message. A variation on the name "Dark". (AUDIO: Masterpiece)
 * Banto Zame: Posed as Zame when the latter's impersonation of the Doctor landed him in trouble. (AUDIO: The One Doctor)

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)
 * Norman Brown: Used, with a West Country accent, to hide his identity from Sheldukher. (PROSE: The Highest Science)
 * 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. At no point did the Doctor use this alias himself. (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

 * John Doe: In a continuation of the circumstances described above for the Seventh Doctor, the Eighth Doctor technically continued to be "John Doe" immediately after his regeneration and was referred to by this name after his escape from the morgue was discovered. (TV: Doctor Who)
 * 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)
 * Doctor Doctor: Inadvertently introduced as such when talking to Doctor Charles Roley and his staff; Samantha Jones dismissed it as an amusing irony, with the Doctor explaining that this was why he preferred to just be known as 'Doctor' (PROSE: The Taint).
 * 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 had earlier taken up the alias 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)
 * 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)
 * 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)
 * Dr Frankenstein: When meeting Mary Shelley and the other inhabitants of Villa Diodati in Switzerland, the half delirious Doctor introduced himself this way. (AUDIO: Mary's Story)
 * Bert Higgins: While on Nixyce VII. (AUDIO: The Traitor, Eyes of the Master)

War Doctor

 * The Warrior: The moniker the Doctor chose to take in the Fifth Segment of the Time War upon his eighth regeneration, (PROSE: The Stranger) and his rejection of his "Doctor" title. (TV: The Night of the Doctor) By the time he went back to the First Segment of the war, he had stopped calling himself a warrior as well. (PROSE: The Stranger) Clara Oswald later referred to him as "the Warrior" to differ himself from the Tenth and Eleventh Doctors. (TV: The Day of the Doctor)
 * Prisoner 101: A designation given to him by Cardinal Ollistra when she arrested him as a war criminal. (AUDIO: Legions of the Lost)
 * Greybeard: A descriptive name given to him by Kalan during the Ollistra-rescuing operation on Rovidia (AUDIO: The Eternity Cage)
 * The Lord of Death: One of the Volatix Cabal identified the Doctor as such during the Time War. (COMIC: The Organ Grinder)

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 tricorder, the Doctor used the alias Dr McCoy (after Dr. Leonard "Bones" McCoy) when dealing with a group of soldiers (Donna called herself Captain Kirk, after James T. Kirk). (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)
 * Doctor Venkman: In New Orleans during Jazz Age. (COMIC: The Jazz Monster)

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)
 * 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)
 * 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)
 * Skovox Artificer: Using a voice manipulator, the Doctor was able to convince a Skovox Blitzer that he was its superior and got it to deactivate itself. (TV: The Caretaker)
 * Odin: After being captured by Vikings, the Doctor tried to pass himself off as Odin to gain his freedom, but was out done when another Odin showed up. (TV: The Girl Who Died)
 * Doctor Disco: When calling Clara on the phone. (TV: The Zygon Invasion)
 * Doctor Funkenstein: When introducing himself to Walsh. (TV: The Zygon Invasion)
 * John Disco: A mix between the Doctor's nickname of "Doctor Disco" which he had used earlier (TV: The Zygon Invasion) and his go-to alias "John Smith", used with the psychic paper to try and put at ease a pair of concerned officers who were driving to the crash site of Boat One and found him and Osgood to be suspicious characters. (TV: The Zygon Inversion)
 * Doctor Puntastic: Coined by the Doctor after he cracked a pun to Bonnie. (TV: The Zygon Inversion)
 * Patient 89: The Doctor's number while waiting at New Hippocrates. (COMIC: The Day at the Doctors)
 * Doctor Mysterio: A young Grant Gordon's name for the Doctor, if he were a comic book character. The Doctor loved it, and said he'd have it. Grant used the name again after he encountered the Doctor once more as an adult. (TV: The Return of Doctor Mysterio)
 * Special Agent Dan Dangerous from Scotland Yard: The Doctor made up this name when he first introduced himself to Lucy Fletcher. (TV: The Return of Doctor Mysterio)

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.
 * 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

 * Joseph: Used numerous times mockingly due to his multi coloured coat. (AUDIO: The Light at the End)
 * 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)
 * Lazarus: The code-name that the Forge used to refer to the Sixth Doctor. (AUDIO: Project: Lazarus, PROSE: Project: Valhalla)
 * 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)
 * Time's Champion: A title given to the Doctor for his service to Time during his seventh incarnation. (PROSE: Love and War)
 * Star Traveller: Referred to a such by William Blake. (PROSE: The Pit)
 * 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

 * The Predator of the Daleks: A descriptive term for the Doctor used by the Daleks, (TV: Asylum of the Daleks) that originated during his war incarnation. (PROSE: Engines of War)
 * 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)
 * Grandad: A nickname given by the Eleventh Doctor due to the War Doctor's aged appearance. (TV: The Day 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)
 * Captain Grumpy: A nickname given by the Eleventh Doctor due to the War Doctor's serious personality. (TV: The Time of the Doctor)
 * Dalek Killer: One of the names awarded to the War Doctor by the Daleks. (PROSE: Engines of War)
 * The Great Scourge: One of the names awarded to the War Doctor by the Daleks. (PROSE: Engines of War)
 * The Living Death: One of the names awarded to the War Doctor by the Daleks. (PROSE: Engines of War)
 * The Executioner: One of the names awarded to the War Doctor by the Daleks. (PROSE: Engines of War)
 * The Doctor of War: a name that arose as part of a saying used to describe him during the Time War. Gastron quoted it as, "The first thing you will notice about the Doctor of War... is he's unarmed. For many, it's also the last." (TV: Hell Bent)

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)
 * Big Nose: The Tenth Doctor refers to this incarnation as such when questioning the Alternate Twelfth Doctor about his whereabouts. (COMIC: Four Doctors)

Tenth Doctor

 * Merlin: The Tenth Doctor would later claim that he was called Merlin by King Arthur. (COMIC: Fugitive)
 * 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)
 * 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)
 * Time Lord Victorious: A very brief title the Tenth Doctor was going to start using after interfering with a fixed point in time and saving Adelaide Brooke from her death. When Adelaide killed herself to restore the timeline, causing several changes that the Tenth Doctor instantly saw because of what he had done, the Tenth Doctor was filled with extreme guilt and horror over what he did, quickly abandoning the 'Time Lord Victorious' title. (TV: The Waters of Mars)

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)
 * 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 travelers (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)
 * The Caretaker: Called as such by both staff and students of Coal Hill School during his brief reign as the school's caretaker. (TV: The Caretaker)
 * 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 by Kate Stewart and due to the Doctor being made president of Earth during the Cyberman invasion Missy orchestrated. (TV: Death in Heaven)
 * Skeleton Man: A name given to him by Shona McCullough, who had mistaken him for a ghost when they first met. (TV: Last Christmas)
 * The Cat in the Hat: Referred to as such by Johnny Dragotta. (COMIC: Gangland)
 * Ancient One: Referred to as such by the Skinks. (COMIC: Hyperballad)
 * The Magician: Referred to as such by Bors. (TV: The Doctor's Meditation)
 * The Eyebrows: A nickname given to him by Missy to differentiate the twelfth incarnation from the other Doctors. (TV: The Witch's Familiar)
 * Doctor Disco/Doctor Funkenstein: At some point the Doctor began referring to himself as Doctor Disco on answering machines and Doctor Funkenstein in public. (TV: The Zygon Invasion)
 * The Scary Doctor: While not actually being used, the Twelfth Doctor did fear his two predecessors would come to know him as the 'scary Doctor' because of his darkening personality. (COMIC: Four Doctors)
 * Basil: The Doctor claimed his first name was Basil when questioning Osgood about what her given name was. (TV: The Zygon Inversion)
 * John Disco: Deciding to alter the John Smith alias the Doctor introduced himself as Dr. John Disco, something even Bonnie, the Zygon duplicate of Clara Oswald, found odd. (TV: The Zygon Inversion)
 * The Great Destruction of the Universe: Called so by the Shadow Kin. (TV: For Tonight We Might Die)

Other

 * The Valeyard: A version of the Doctor created sometime between his twelfth and final incarnations. (TV: The Ultimate Foe, The Name of the Doctor)
 * 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)
 * The Storm: Another title in reference to the Doctor by the Great Intelligence (TV: The Name of the Doctor)
 * The Slaughterer of the Ten Billion: A damning title by the Great Intelligence in reference to the Doctor's final battle on Trenzalore (TV: The Name of the Doctor)
 * Damsel: A codename for the Doctor that River Song used on her missions, owing to the fact that he "needed rescuing a lot" of the time. (TV: The Husbands of River Song)

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 narrative; 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. However, in the 2015 episode Hell Bent, this incarnation was referred to by the alternate name the Doctor of War.
 * 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."