Doctor Who? running joke

When Doctor Who first broadcast on 23 November 1963, the understanding was made that "the Doctor" was the primary alias used by the main character. Distinctly, the series did not choose to depict "Who" as the character's last name, despite the overall use of "Doctor Who" in most expanded media before the mid-1970s.

Because of this, the most common way that the series name was name-dropped was via the asking of the question: "Doctor who?" The following article discusses every documented instance of this gag being used, alongside any humorous reference to "Who" potentially being part of the Doctor's identity. This list will not document every story to depict Dr. Who as the character's name outright, such as the TV Comics or the Peter Cushing films.

First Doctor

 * The gag first occurred in the first episode of the first Doctor Who story, An Unearthly Child, when Ian Chesterton said, "Well just open the doors, Doctor Foreman." The Doctor replied, "Eh, Doctor who? — what's he talking about?" According to the DVD production subtitles, the response was actually added by William Hartnell himself.
 * In the second episode, Barbara also referred to the Doctor as "Doctor Foreman", to which Ian replied, "That's not his name. Who is he? Doctor who? Perhaps if we knew his name we might have a clue to all this."
 * In The Keys of Marinus, when Ian was a suspect for murder, he was told to find someone to speak for him at the tribunal. He said he knew someone in the city, and when asked, "Who is he?" he replied, "Who?", smiled, and continued, "He's a Doctor."
 * In the final episode of The Chase, the Doctor attempted to pass himself off to a group of Daleks as the (now-destroyed) robot duplicate of himself. It didn't work, and after escaping the Doctor said, "They now know who's Who." According to the DVD production notes the script capitalises the second "Who" as an in-joke. (The production notes also indicate that Terry Nation's original script for the story had no less than two lines of dialogue that would have directly referred to the Doctor by the name Doctor Who.)
 * At the beginning of The Time Meddler, Vicki said (referring to Ian and Barbara, who had just left), "I shall miss them, Doctor," to which the Doctor replied, "Who?"
 * In The Gunfighters, the Doctor hesitantly introduced himself to Bat Masterson by the alias of Doctor Caligari. Masterson asked, "Doctor Who?" and the Doctor answered, "Yes, er, quite right."
 * In The War Machines, WOTAN ordered Dodo Chaplet to send the Doctor with the command, "DDDOCTORR WHOO ISS RREQUIREDD". Later in the serial, some of the scientists used the name "Dr. Who" to refer to the Doctor as well. This is the only time in the series that the Doctor was directly called "Doctor Who." This reportedly caused fans to send angry mail to the production team.

Second Doctor

 * The Doctor introduced himself as "Doktor von Wer" (German for "Doctor (of) Who") to which the sergeant asked, "Doctor who?" The Doctor replied "That's what I said." (TV: The Highlanders)
 * When the Doctor wrote a note to Professor Zaroff, he signed it "Dr. W." (TV: The Underwater Menace)
 * A moment after meeting the Doctor for the first time, Colonel Crichton asked, "Who was that strange little man?". An UNIT employee answered, "The Doctor". Crichton replied, "Who?", followed by an immediate cut to the Brigadier, in the middle of an unrelated conversation with the Doctor, saying "Yes". The three lines, played rapid fire as they are, tip the hat to both the in-joke and the Abbot and Costello "Who's on First" sketch. (TV: The Five Doctors)

Third Doctor

 * In The Curse of Peladon, the Earth representative was outraged that the guards wouldn't let her in the palace, because she was the rightful representative of Earth. The Doctor claimed to be the representative of Earth. The Earth representative then asked, "Doctor? What Doctor? Doctor who?"
 * In The Mutants, the Investigator asked Cotton, "Doctor... who, did you say?"
 * The Doctor's vehicle, Bessie, carried the licence plate "WHO 1". (However, the vehicle introduced later in Pertwee's era, while referred to as the Whomobile in publicity and by Pertwee himself, is never referred to by this name on screen.)

Fourth Doctor

 * Continuing the in-joke from the Third Doctor era, the Fourth Doctor drove Bessie with its WHO 1 licence plate on one occasion. (TV: Robot)
 * During her initial meeting with the Doctor, Tegan referred to him as "Doctor whoever-you-are". (TV: Logopolis)

Fifth Doctor

 * When Lady Cranleigh was introduced to the Doctor, she said, "How do you do? Doctor... who?" (TV: Black Orchid)

Sixth Doctor

 * When Russell found the Doctor and Peri in the London sewers, he demanded their names, leading to the exchange: "Shall it suffice to say that this is Peri and I am known as the Doctor?""Doctor who? "Actually, it's more a matter of what. I'm a doctor of medicine, science, philosophy –" (PROSE:Attack of the Cybermen'')

Seventh Doctor

 * A more serious version was used as Lady Peinforte asked Ace, "Doctor who? Have you never wondered where he came from? Who he is?" in an attempt to blackmail the Doctor into surrendering his component of Nemesis. The last line of the story is Ace asking, "Doctor? Who are you"'" (TV: Silver Nemesis'')
 * The joke turned metafictional in Battlefield when the Doctor drove Bessie once again, but the licence plate had been inexplicably updated to "WHO 7".
 * In TV: Dimensions in Time, Romana is caught in a garage by Phil and Grant Mitchell. When she is asked what she is doing, she responds "Looking for the Doctor." Phil and Grant tell her that Doctor Legg is at number one on Albert Square, she responds "Doctor who?"

Eighth Doctor

 * Although an ambiguous reference, in the Doctor Who TV movie, when stricken with amnesia, the Eighth Doctor asks himself "WHO AM I?"

Ninth Doctor

 * In Rose, Rose's online search for information about the Doctor brought her to a website titled "Who is Doctor Who?"
 * In The Empty Child, when Rose introduced the Doctor to Jack as "Mr. Spock" she said to him "What was I supposed to say? You don't have a name! Don't you ever get tired of 'Doctor'? Doctor who?"
 * According to Steven Moffat a more explicit use of the joke was planned but cut. The Doctor was to have responded to Rose's bestowal of the name Mr. Spock by saying "I'd rather Doctor Who than Star Trek."
 * When meeting Margaret Blaine's (Blon Fel-Fotch Passameer-Day Slitheen in disguise) secretary Idris Hopper in Boom Town this discussion occurred:
 * The Doctor: "Just go in there, and tell her the Doctor would like to see her."
 * Idris: "Doctor who?"
 * The Doctor: "Just the Doctor. Tell her exactly that. The Doctor."

Tenth Doctor

 * In The Christmas Invasion, the newly regenerated Tenth Doctor fainted in front of Jackie Tyler and Mickey Smith after landing the TARDIS. After Rose told the pair that he was the Doctor, Jackie thought of the Ninth Doctor and not knowing the concept of regeneration, asked Rose, "What d'you mean, 'That's the Doctor'? Doctor who?"
 * In The Girl in the Fireplace, after the Tenth Doctor and Reinette read each others minds, Reinette said sadly, "Doctor who? It's more than just a secret", before inviting him to dance.
 * In Blink, Sally Sparrow and Larry Nightingale watched an Easter egg on a DVD. Sally said, "The Doctor." and Larry replied, "Who's the Doctor?".
 * In The Next Doctor, the Doctor introduced himself to Rosita as "the Doctor" and she replied, "Doctor who?".
 * Christina de Souza in Planet of the Dead asked multiple questions concerning the "the Doctor's" identity.

Eleventh Doctor

 * In The Impossible Astronaut, Charles II burst into a room and asked Matilda, "Where's the Doctor?" She replied, "Doctor who?
 * In The Impossible Astronaut, Canton Everett Delaware III asked Amy about the Doctor, saying, "Doctor who, exactly?"
 * In Let's Kill Hitler, when the Teselecta attacked Melody Pond for killing the Doctor, the Doctor emerged from the TARDIS with a different outfit, saying "Sorry, did you say she killed the Doctor? The Doctor? Doctor Who?"
 * In The Wedding of River Song, Dorium Maldovar claimed that "Doctor Who?" was a question that should never be answered. He said that the Silence believed that when the question was asked, "silence must fall".
 * In Asylum of the Daleks, the Daleks' knowledge and memories of the Doctor are deleted from their Pathweb network by Oswin Oswald. Upon returning to the Dalek Parliament for the TARDIS, the Doctor tests this by telling them his name and asking why they won't attack him. He is told that the title of Doctor is meaningless, and thousands of Daleks began chanting "Doctor Who?" as he left in the TARDIS. Afterwards, the Doctor himself was also heard chanting this out of apparent joy.
 * In The Angels Take Manhattan, the Doctor asked River "Weren't you the woman who killed the Doctor?" She replied, in reference to his efforts to delete himself from all the databases in the universe, "Doctor who?"
 * In The Snowmen, the question was asked four times. First, when Vastra told the Doctor that all his relationships always started with the same two words, implied to be "Doctor who?": this was immediately confirmed by Clara who popped into the carriage (notably from the roof and up side down) and asked "Doctor? Doctor who?". Second, when the Doctor asked "Clara who?" Clara countered "Doctor who?" to which the Doctor responded that it's a dangerous question. Third, when Clara asked Jenny Flint if she knew the Doctor, she responded with a smirk: "Doctor who?". The fourth time the expression was used by the Doctor as a way of announcing himself just before destroying the Ice Governess.
 * In The Bells of Saint John, The Doctor stated that he often forgets how much he likes being asked "Doctor who?" when he asks Clara Oswald to repeat it several times.
 * In Hide, when the Doctor introduces himself, Alec asks him, "Doctor what?," to which the Doctor responds, "If you like."
 * In The Day of the Doctor, The Curator (played by Tom Baker, the same actor who played the Fourth Doctor) ends his scene by asking the question "Who knows?" He then repeats the phrase while tapping his nose, suggesting a secret that you keep to yourself, ie "Who knows."

Twelfth Doctor

 * In Dark Water,  when Missy explains that her heart is maintained by "the doctor", the Doctor asks "Doctor Who?" before she calls for her employee Dr. Chang.

K9 and Company

 * When Brendan Richards asked, "Who is the Doctor?", K9 Mark III responded, "Affirmative."

The Sarah Jane Adventures

 * In Revenge of the Slitheen, the Slitheen told Sarah Jane that members of their family died at 10 Downing Street. Sarah Jane tried to tell them that she might know "what happened. Or rather, who happened."
 * The joke was hidden within a sentence in The Temptation of Sarah Jane Smith. Sarah Jane was hesitant to go into the past for fear of altering time. When the kids reminded her that she routinely did that in the TARDIS, she responded, "I was with the Doctor who knew what he was doing."

Fifth Doctor

 * In AUDIO: The Kingmaker, the publishing robot that came to interrogate the Doctor about his failure to produce his final in a series of children's books entitled Doctor Who Discovers referred to him as 'Doctor Who'. When this was questioned by Peri and Erimem, the Doctor explained that "some idiot" at the publishing company had misprinted the title, which was originally intended to be The Doctor, Who Discovers...

Sixth Doctor

 * In AUDIO: Real Time, the President suggested contacting "the Doctor." His subordinate, Dean, responded, "Who?" (This scene is exclusive to the story's audio release. It does not appear in the webcast version.)
 * The summary for AUDIO: Pier Pressure, written from the point of view of Max Miller, features the line "No, this bloke called himself the Doctor. Doctor who, you ask?"

Second Doctor

 * In PROSE: The Dark Path, after the Second Doctor introduced his companions and himself: 'This is Victoria, Jamie, and I'm the Doctor', Adjudicator Secular Brandauer asked: 'Doctor who?' (to which the Doctor replied: 'Oh, don't you mean Doctor whom? I do hate to be contrary, but...' and changed the subject).

Fourth Doctor

 * In PROSE : Evolution, Breckinridge addressed the Doctor as "Dr. Smith," to which Abercrombie asked: "Doctor who?"
 * In PROSE: A Device of Death, when the amnesiac Fourth Doctor was reminded of his title and he said: "That's right; I'm the Doctor', he was asked: 'Dr who?', to which he replied: 'Who? Who, who, who. Possibly, possibly...'
 * In PROSE: System Shock, during a conversation with a computer the Doctor typed in the question: 'You know Who I am?' (with a capital 'W').

First Doctor

 * In PROSE: Salvation, General Marchant at one point addressed the First Doctor as 'Doctor Whoever-You-Are'.

Others

 * Special note should be given to the novelisation Doctor Who and the Zarbi for rendering any opportunities for the joke moot by referring to the Doctor throughout by the name "Dr. Who". This stands as the only official novel ever published to break the naming convention.
 * The blurb of the novelisation of Robot (TV story), named Doctor Who and the Giant Robot, has the Brigadier ask "WHO will be next?" upon the Doctor's regeneration. The actual novel replaces this with "Here we go again..." as per the television story.

First Doctor

 * In PROSE: 64 Carlysle Street, Sergeant Dunston referred to the First Doctor as 'this Doctor Whoever-he-was'.

Fifth Doctor

 * In PROSE: A Town Called Eternity, the Fifth Doctor introduced himself to Sarah Brown, who asked, "Doctor who?"

Seventh Doctor

 * In PROSE: Log 384, the Seventh Doctor started to introduce himself to Edward Grainger, paused, and said, "Let's go with Professor, shall we?" to which Edward asked, "Professor who?"

Unspecified Doctor

 * In PROSE: The Feast of Seven... Eight (and Nine), two (unspecified) incarnations of the Doctor asked each other knock-knock jokes, but they fell flat: 'Doctor.' 'Doctor who? Who's that?'

Third Doctor

 * In PROSE: Prisoners of the Sun, Liz scribbled "Doctor – who?" in her diary, under a page headed "unfinished business".

Fourth Doctor

 * In COMIC: Hubert's Folly, Sir Julian Hubert called the Doctor "Doctor whoever-you-are".

Fourth Doctor

 * In COMIC: Black Destiny, the Fourth Doctor and his companions were mistaken for members of the World Health Organisation, or W.H.O.

Sixth Doctor

 * When questioned "Doctor Who?" on Sylvaniar, the Doctor responded "Quite." (COMIC: Revelation!)

Eleventh Doctor

 * When reunited with his past companions Ian Chesterton and Barbara Wright, after announcing that he was the Doctor, Barbara asked "Doctor Who?" (COMIC: Hunters of the Burning Stone)

In pop culture

 * A common knock-knock gag is for someone to say "Doctor" when asked who is at the door, making the first person ask "Doctor Who?" at the second. "Correct" or "No, a different Doctor," or even "If you know who I am, why won't you let me in!". William Hartnell's real-life granddaughter Jessica Carney would often be told this joke as a child by her peers, and grew very annoyed with it. In a Never Mind the Buzzcock special that was based on Doctor Who, David Tennant made the joke with Bernard Cribbins.