In the long-running BBCtelevision science fiction programme Doctor Who and related works, the term "companion" refers to a character who travels with, or shares adventures with, the Doctor. In most Doctor Who stories, the primary companion acts as an audience surrogate by providing the lens through which the viewer is introduced to the story, and often, the series itself.
The companion character often furthers the story by asking questions (which helps the audience understand too) and getting into trouble; also by helping, rescuing, or challenging the Doctor. This designation is applied to a character by the show's producers and appears in the BBC's promotional material and off-screen fictional terminology. The Doctor also refers to the show's other leads as their "friends" or "assistants"; the British press have also used the latter term.
In the earliest episodes of Doctor Who, the dramatic structure of the programme's cast was rather different from the hero-and-sidekick pattern that emerged later. Initially, the character of the Doctor was unclear, with uncertain motives and abilities.[1] The primary protagonists were schoolteachers Ian Chesterton and Barbara Wright, who provided the audience's point of view in stories set in Earth's history and on alien worlds. Ian in particular served the role of the action hero. The fourth character was the Doctor's granddaughter, Susan, who (though initially presented as an "unearthly child") was intended as an identification figure for younger viewers.[2]
Carole Ann Ford, who played Susan Foreman, became unhappy with the lack of development for her character[3] and chose to leave in the show's second series. The character of Susan was married off to a freedom fighter and left behind to rebuild a Dalek-ravaged Earth. Doctor Who's producers replaced Susan with another young female character, Vicki.[4] Similarly, when Ian and Barbara left, the "action hero" position was filled by astronaut Steven Taylor.[5] This grouping of the Doctor, a young heroic male, and an attractive young female became the programme's pattern throughout the 1960s.
When the programme changed to colour in 1970, its format changed: the Doctor was now Earth-bound and acquired a supporting cast by his affiliation with the paramilitary organisation United Nations Intelligence Taskforce (UNIT). The Third Doctor, more active and physical than his predecessors, made the role of the "action hero" male companion redundant. In the 1970 season, the Doctor was assisted by scientist Liz Shaw and Brigadier Lethbridge-Stewart, along with other UNIT personnel. The intellectual Shaw was replaced by Jo Grant in the following season, and as the programme returned to occasional adventures in outer space, the format shifted once more: while UNIT continued to provide a regular "home base" for Earth-bound stories, in stories on other planets, the Doctor and Jo became a two-person team with a close, personal bond. This pattern, the Doctor with a single female companion, became a template from which subsequent eras of Doctor Who rarely diverged.
In 1974, the character of Harry Sullivan was created by the production team when it was expected that the Fourth Doctor would be played by an older actor who would have trouble with the activity expressed by his predecessor. The role went to 40-year-old Tom Baker, and the part of Harry, no longer required for the action role, was dropped after one season.[6]
In the Fourth Doctor's final season (1980-1981), he acquired three companions (Adric, Tegan, and Nyssa), and this situation continued under the Fifth Doctor for much of his first season. Adric was written out by the method, unusual within the series, of being "killed off" in the serial Earthshock. By the time of the Sixth Doctor in 1985, a single companion had become standard again.
When the series returned in 2005, a single female companion remained the standard format, though intermittent and short-term companions also featured. More consistent exceptions occurred between series 5 and 7, when the Eleventh Doctor travelled with Amy Pond and Rory Williams, and series 10, where the Twelfth Doctor appeared alongside Bill Potts and Nardole. In conjunction with the introduction of the first female Doctor in 2018, the Thirteenth Doctor's era features multiple companions (both male and female) throughout.
Although the term "companion" is designated to specific characters by the show's producers and appears in the BBC's promotional material and off-screen fictional terminology, there is no formal definition that constitutes such a designation. The definition of who is and is not a companion becomes less clear in the newer series.[7] During the Doctor's latest incarnations, his primary companions, such as Rose Tyler and Martha Jones, have fulfilled a distinct dramatic role, more significant than other, less prominent TARDIS travellers such as Adam, Jack, and Mickey. The British press referred to Martha as the "first ethnic minority companion in the 43-year television history of Doctor Who"[8] despite the presence of Mickey Smith in the previous series—including several episodes in which he travelled in the TARDIS with the Doctor.
The opening credits do little to clarify the situation. In the first two series of the renewed programme, the only supporting actor to receive a title credit is Billie Piper, although short-term companions Bruno Langley (Adam Mitchell), John Barrowman (Jack Harkness) and Noel Clarke (Mickey Smith) all appear. In the third series, Barrowman receives a title credit for his return to the show alongside permanent cast member Freema Agyeman, and in series four Agyeman is restored to the opening titles for her return arc as Martha Jones. Series four also gives Agyeman, Piper, Barrowman, and Elisabeth Sladen title billing for their reappearances in the final two-parter. Clarke also reprises his role in the series four finale; although listed as a companion alongside the other actors on the BBC Doctor Who website,[9] Clarke is not credited in this way. In "The End of Time", John Simm receives title billing for his antagonist role as the Master, ahead of Bernard Cribbins as companion Wilfred Mott. In subsequent years, Claire Skinner, Nick Frost and Mark Gatiss have received title credits in special episodes for roles that are not considered companions, as does Piper for her non-companion return in "The Day of the Doctor".
Companions in the new series also have a more flexible tenure than their classical predecessors. Several companion characters have returned to the series after leaving the Doctor's company, most notably in the Series Four finale "The Stolen Earth"/"Journey's End" (2008), which features a record eight past, present and future companions: Donna is joined by a returning Rose, Martha, Jack, Sarah Jane, and Mickey, while past companion K9 and future companion Wilfred Mott make appearances. This tendency, plus the increase in "one-off" companions like Astrid Peth and Jackson Lake, has further obscured the matter of who is and is not a companion.[7]
The Doctor's companions have assumed a variety of roles—involuntary passengers, assistants (particularly Liz Shaw), friends, and fellow adventurers; and, of course, he regularly gains new companions and loses old ones. Sometimes they return home, and sometimes they find new causes—or loves—on worlds they have visited. A few companions have died during their travels with the Doctor, such as the 12th Doctor's companion Bill Potts. Some have taken trips in the TARDIS by accident like Rose's mother, Jackie Tyler.
Most companions travel in the TARDIS with the Doctor for more than one adventure. Sometimes a guest character takes a role in the story similar to that of a companion, such as photographer Isobel Watkins, who plays a significant role in The Invasion (1968), or Lynda Moss in "Bad Wolf" and "The Parting of the Ways" (2005). In the revived era, some guest characters have gained companion status such as Mickey Smith, River Song, Wilfred Mott, and Craig Owens.
Despite the fact that the majority of the Doctor's companions are young, attractive females, the production team for the 1963–89 series maintained a long-standing taboo against any overt romantic involvement in the TARDIS: for example, Peter Davison, as the Fifth Doctor, was not allowed to put his arm around either Sarah Sutton (Nyssa) or Janet Fielding (Tegan Jovanka).[10] The taboo was controversially[11] broken in the 1996 television movie when the Eighth Doctor was shown kissing companion Grace Holloway. The 2005 series played with this idea by having various characters think that the Ninth Doctor and Rose Tyler were a couple, which they vehemently denied. Since the series revival, the Doctor has kissed many of his companions, including Rose and Jack, although each instance was not necessarily in a romantic context (see also "The Doctor and romance"). In Series 2 of the revival, the Tenth Doctor and Rose develop a romantic connection.[5] Rose mentions sharing a mortgage with him if he were to ever be trapped with her in "The Satan Pit". At the end of Series 2, in "Doomsday", Rose and the Doctor are forcibly separated. The Doctor "burns up a sun to say goodbye" and Rose tells him "I love you". Rose and Martha each developed romantic feelings toward the Doctor. On the opposite side of the same coin, Amy reacted to the stress of her adventures by very aggressively trying to seduce the Doctor on the eve of her own wedding, despite being in love with her fiancé Rory; the Doctor forcibly pushed her off of himself, though she did not immediately cease her pursuit.[12] The Eleventh Doctor also formed a romantic connection with occasional companion River Song,[13] later marrying her.[14]
Previous companions have reappeared in the series. Brigadier Lethbridge-Stewart reunited with later incarnations of the Doctor in Mawdryn Undead and Battlefield. He and Sergeant Benton began as returning characters in the first place, having appeared with the Second Doctor in The Web of Fear and again in The Invasion, prior to starting their full-time association with the Third and Fourth Doctors. Tegan Jovanka was the first full-time companion to part from the Doctor and subsequently return to full-time companionship, although the break in her tenure had been pre-planned.
Most reappearances of companions in the original series, however, were for anniversary specials such as "The Five Doctors" and Dimensions in Time, both of which also featured multiple Doctors. One former companion, Sarah Jane Smith, together with the robotic dog K-9, appeared in four and two episodes, respectively, of the revived series[15] more than twenty years after their last appearances in the 20th anniversary story "The Five Doctors" (1983). The character of Sarah Jane also headed up a Doctor Who spin-off, The Sarah Jane Adventures, with K-9 until Sladen's death. Another companion, Captain Jack Harkness, is the lead character in the spin-off BBC science fiction programme Torchwood. Not only have these former companions continued to make appearances on Doctor Who, they have sometimes been accompanied by some of their own companions from the spin-offs when doing so, including Jack's colleagues Gwen Cooper and Ianto Jones, and Sarah Jane's 'family' Mr Smith, Luke Smith and K-9 Mark IV. Other former companions from both the classic era and revived series have also returned as guest stars in the spin-offs, including Martha Jones on Torchwood, and Brigadier Lethbridge-Stewart and Jo Grant on The Sarah Jane Adventures. K-9 Mark I has also been spun off into its own series, albeit with an independent continuity.
When Doctor Whoreturned to television in 2005, the companion characters played a slightly different role, partly due to a strong focus on the character of Rose Tyler and characters connected to her. For example, although Adam Mitchell was a companion by the standard definition, he appeared in only two episodes and was arguably a less significant part of the 2005 series than Rose's sometime boyfriend Mickey Smith, who was not technically a companion but appeared in five episodes. Mickey later gained full-fledged companion status when he travelled in the TARDIS in the 2006 episode "School Reunion". In that episode, Sarah Jane Smith referred to Rose as the Doctor's "assistant", a term to which the latter took offence. This exchange might be regarded as indicating the new series' shift in approach to the companion role. Adam was also far less significant than Rose's mother, Jackie Tyler, who was a frequently recurring character who travelled in the TARDIS, yet is not considered a companion.
In the classic era, companions' friends and families were rarely depicted, and almost all were kept unaware of the true nature of the Doctor and the TARDIS.
Conversely, families and friends of most companions in the revived era are extensively depicted, and their adventures with the Doctor are generally not kept secret. The revived era has also featured a number of companions related to other companions by blood or marriage (Donna Noble's grandfather Wilfred Mott; Amy Pond's fiancé (later husband) Rory Williams, and the couple's daughter River Song; former companions Mickey Smith and Martha Jones who married subsequent to their companionship; Graham O'Brien and step-grandson Ryan Sinclair).[16] No such relationships occurred among companions in the classic era, although original companions Ian Chesterton and Barbara Wright are reported in the revived era to have married subsequent to their companionship, and Ben Jackson and Polly are likewise reported to be together.[17] The families of some classic-era companions too have been depicted in the revived era, such as Jo Grant (now known as Jo Jones)'s grandson Santiago Jones;[18] and Sarah Jane Smith's parents,[19] adopted son Luke Smith, adopted daughter Sky Smith, and alternate timeline fiancé Peter Dalton;[20] and Alistair Lethbridge-Stewart's daughter Kate Stewart.[21]
Another change in the revived era is the depiction of many companions' pre-Doctor lives, particularly their childhoods; no companion was so depicted in the classic era. Companions Rose Tyler,[22] Mickey Smith,[23] Adelaide Brooke,[24] Amy Pond,[25] Rory Williams,[26] River Song[27] and Clara Oswald[28] have all been portrayed in their youths by juvenile actors on Doctor Who; the pre-companionship lives of the Pond-Williams-Song family being particularly well-documented. Companions Jack Harkness[29] and Sarah Jane Smith[30] have also been depicted in their youths on their respective spin-off series.
In the original run of the show, companions were mostly written as leaving of their own accord, with only a few exceptions.[31] The first death of a regular companion was of Adric, in the 1982 serial Earthshock.[32] This is different in the revived era, with companions more often given tragic endings and the show exploring the theme of loss more.[31] Demaris Oxman makes further distinction of the way this theme is explored by different showrunners, arguing that companions in Steven Moffat's time as showrunner tended to have more tragic endings, while Russell T. Davies wrote departures closely tied to each companion's character.[32]
The impact of such losses has been explored within the show. For example, the loss of Amy and Rory Williams drives the Eleventh Doctor into solitude in Victorian London where he refuses to get involved in the world's affairs anymore.[33]Series 9 dealt with the Twelfth Doctor's growing fear over the potential of losing Clara Oswald.[nb 1] Her death in "Face the Raven" leads the Doctor to undertake extreme measures to undo her fate, as depicted in the Series 9 finale "Hell Bent". The impact of the death of his wife, River Song, is a subplot of both "The Husbands of River Song" and "The Return of Doctor Mysterio".
Steven Moffat, showrunner between 2010 and 2017, has stated that companion deaths are "wrong for Doctor Who", explaining that he does not believe the show should represent the "grittiness" of real life.[34]
Several companions are shown to have died in the show's history:
Katarina, killed in episode 4 of The Daleks' Master Plan when she opens the airlock of a spaceship after being taken hostage by a convict.
Sara Kingdom is killed in episode 12 of The Daleks' Master Plan when she undergoes extreme ageing as a side effect of the First Doctor's activation of a Time Destructor device.[35]
Adric dies at the end of Episode 4 of Earthshock while trying to prevent the explosion of a bomb-laden space freighter in Earth's atmosphere.
Kamelion, an android companion, is destroyed by the Fifth Doctor in Episode 4 of Planet of Fire as an act of mercy after Kamelion is taken over by the Master and asks the Doctor to destroy him.
K9 Mark III sacrifices himself in "School Reunion" to save the Doctor and his friends from a group of aliens. The subsequent K-9 Mark IV that the Doctor leaves with Sarah Jane tells her that the Mark III's files have been transferred to the new machine.
Astrid Peth sacrifices herself to kill Max Capricorn by driving him into a reactor core at the end of "Voyage of the Damned". The Tenth Doctor partially resurrects her and sends her atoms into space.
Adelaide Brooke kills herself in "The Waters of Mars" to preserve a fixed point in time.
Others are implied (or said) to have died years after parting company with the Doctor:
Sarah Jane Smith is confirmed to be dead by 2023 in "The Giggle" by the Fifteenth Doctor when talking to the Fourteenth Doctor about what they had lost, adding that they "loved her". The 2020 webcast ‘Farewell Sarah Jane’ depicts her funeral, with numerous past companions attending as well as the children she mentored in The Sarah Jane Adventures.
Clara Oswald is implied to have at some point died a permeant death but is able to continue living indefinitely after departing the Doctor.
In The Trial of a Time LordPeri Brown is killed by King Yrcanos in Mindwarp after her brain is replaced by that of Kiv, a member of the Mentor race. In The Ultimate Foe, however, it is revealed that Peri had not been killed and had become Yrcanos's consort.
Jack Harkness is killed by Daleks, but is brought back to life and given immortality by Rose Tyler in "The Parting of the Ways". He died several times in Doctor Who and Torchwood, always returning to life soon afterwards. In "Last of the Time Lords" it is hinted that Harkness might become the Face of Boe, who dies peacefully in "Gridlock" after living for billions of years.
River Song sacrifices herself in "Forest of the Dead" to save the Doctor's life, but he uploads a digital copy of her consciousness to the data core. River continues to appear in the series at earlier points in her life, and her post-death consciousness reappears in "The Name of the Doctor"
Rory Williams is killed several times throughout his run. First by the Silurian Restac at the end of "Cold Blood", sacrificing himself to protect the Doctor. He is consumed by a crack in time, which wipes him from existence. Rory reappears in "The Pandorica Opens" as an Auton duplicate created from Amy Pond's memories, and is restored to his old life with the rest of the universe in "The Big Bang". He is shown dying of old age in "The Angels Take Manhattan", in front of himself, Amy Pond, the Eleventh Doctor and his daughter River Song. He and Amy negate the timeline by jumping off a roof, preventing him from being sent further back in time to die of old age downstairs. This kills them both, but they are resurrected when the timeline where they died is negated.[37]
An older version of Amy is erased from existence in "The Girl Who Waited" after helping the Doctor and Rory rescue a younger Amy. When the Doctor admits that both Amys cannot exist in the same timeline, the older Amy chooses to stay behind.
Bill Potts is shot and killed by the colony ship's last crew member to halt the advance of the Cybermen in "World Enough and Time". She is converted into an original Mondasian Cyberman and, during "The Doctor Falls", is saved from her grim fate by being turned into sentient humanoid oil by an alien from her first episode.[38]
Ace is killed by an explosion in the comic storyline Ground Zero while a companion of the Seventh Doctor. This is also contradicted by the Sarah Jane Adventures storyline Death of the Doctor which indicates she is still alive in 2010, no longer travelling with the Doctor, and running a charity called ACE. Ace then appeared in 2022's The Power of the Doctor.
Jamie McCrimmon dies an elderly man in the comic storyline The World Shapers.
Adam Mitchell is killed by an explosion in the comic storyline Prisoners of Time, sacrificing himself to thwart the Master's attempt to destroy reality and saving all eleven Doctors and their companions.
Leela dies long after Gallifrey is destroyed (it is implied that she survived the Time War) in a trilogy of Big Finish's Companion Chronicles stories, where she is held prisoner by an alien race called the Z'nai.
In the 2020 web story Farewell, Sarah Jane, Sarah Jane Smith is said to have died.
The "last serial" column only includes the last serial in which they appeared in a companion role and excludes minor roles, cameos, flashbacks, and so forth. Also, the table refers solely to adventures with the respective Doctor. Some companions who appear with two or more Doctors appear in separate tables.
The final three listed characters, all associated with UNIT during the Third Doctor's exile to Earth, are sometimes considered his companions despite appearing irregularly during his tenure.[46][47]
The Doctor Whospin-off media have seen the creation of new characters acting as new companions to the Doctor. Most of them have been created to feature as companions for the Sixth, Seventh and Eighth Doctor, in the new products presenting themselves as a prosecution of their adventures beyond the TV series, but there also are new companions for other Doctors. None of them have been featured on television, except for the mention of some Big Finish Productions original characters in the minisode The Night of the Doctor; however, some of them have passed from one media to another.
^ abPolly and Ben continue travelling with the Doctor following his regeneration in The Tenth Planet.
^Jamie is played by Hamish Wilson in parts of The Mind Robber episodes 2 and 3, while Frazer Hines was suffering from chickenpox.
^Jamie returns to his own time in The War Games, but later appears in the Sixth Doctor-era story The Two Doctors, again as the Second Doctor's companion.
^First appears in The Web of Fear (as Colonel) and The Invasion alongside the Second Doctor, before appearing as a semi-regular character throughout the Third Doctor's era. He further appears in Robot and Terror of the Zygons alongside the Fourth Doctor, and Mawdryn Undead alongside the Fifth Doctor before serving as the Second Doctor's companion in "The Five Doctors". He subsequently appears in The Sarah Jane Adventures story Enemy of the Bane.
^Sarah continues to travel with the Doctor following his regeneration in Planet of the Spiders, and after her later departure from the series serves as the Third Doctor's companion once more in "The Five Doctors".
^Lethbridge-Stewart appears alongside the Second Doctor as a colonel in The Web of Fear and subsequently as a brigadier in The Invasion.
^The "Mark I" incarnation of K-9, who leaves the Doctor in The Invasion of Time, returns in the independent spin-off series K-9, regenerating into a newer form. A further model of K-9, "Mark III", features in the pilot of K-9 and Company with Sarah Jane Smith, and Doctor Who episode "School Reunion" with the Tenth Doctor and Sarah Jane. Killed and replaced by K-9 Mark IV in the latter episode, he subsequently appears irregularly in The Sarah Jane Adventures, and also the Doctor Who episode "Journey's End".
^Romana leaves the Doctor in Warriors' Gate, and subsequently reappears as the Fourth Doctor's companion in "The Five Doctors" (in footage from Shada).
^ abcAdric, Nyssa and Tegan continue travelling with the Doctor following his regeneration in Logopolis.
^Due to problems with the robotic prop, Kamelion was not featured in the five serials between his first and last stories. Planned scenes in The Awakening were cut and never broadcast.
^Peri continues travelling with the Doctor following his regeneration in The Caves of Androzani.
^The series never establishes how Mel meets the Doctor, who first appears as part of the Doctor's future. Their first meeting is recounted in the Past Doctor Adventures novel Business Unusual and the Big Finish Productions audio-drama The Wrong Doctors.
^Mel continues travelling with the Doctor following his regeneration in Time and the Rani.
^Mel makes a cameo appearance in The Power of the Doctor and becomes a recurring guest star in the tenures of the Fourteenth and Fifteenth Doctors.
^Mickey is introduced in "Rose" as Rose's boyfriend and recurs regularly before becoming a companion.
^Mickey departs in "The Age of Steel" and re-appears in "Army of Ghosts" / "Doomsday" before returning as a companion in "Journey's End". He also appears in "The End of Time".
^After initially refusing to join the Doctor on his travels in "The Runaway Bride", Donna returns as a regular companion from "Partners in Crime". She also appears in "The End of Time".
^Jack rejoins the Doctor in "Utopia" before departing in "Last of the Time Lords", but returns again for "The Stolen Earth" / "Journey's End". He also appears in "The End of Time".
^Previously appears with the Tenth Doctor in "School Reunion".
^Rachel Fewell portrays a younger Adelaide in flashback
^Wilf is introduced in "Voyage of the Damned" and recurs throughout series 4 as Donna's grandfather. He officially becomes a short-term companion in "The End of Time".
^ abAmy and Rory are left by the Doctor in "The God Complex", but appear briefly in "Closing Time" and feature as companions again in "The Wedding of River Song". They appear in the final scene of "The Doctor, the Widow and the Wardrobe", before returning as companions from "Asylum of the Daleks".
^An illusionary Amy appears to the Doctor before his regeneration in "The Time of the Doctor".
^A younger Rory is played by Ezekiel Wigglesworth in "Let's Kill Hitler".
^Rory is killed in "Cold Blood", but returns in "The Pandorica Opens" as an Auton duplicate before being restored to humanity and resuming his travels with the Doctor and Amy in "The Big Bang".
^Earlier incarnations of River Song (as Melody Pond) are played by Sydney Wade in "The Impossible Astronaut" / "Day of the Moon", and Maya Glace-Green and Nina Toussaint-White in "Let's Kill Hitler".
^River first appears alongside the Tenth Doctor in "Silence in the Library" / "Forest of the Dead", introduced as a companion from his relative future who calls the Doctor to her aid. Progressively younger versions of River subsequently summon the Eleventh Doctor in "The Time of Angels" / "Flesh and Stone" and "The Pandorica Opens" / "The Big Bang", before the future Doctor summons her to his death in "The Impossible Astronaut".
^River refuses the Doctor's offer to travel with him permanently in "Day of the Moon". She subsequently features as a companion in "A Good Man Goes to War", "Let's Kill Hitler" and "The Wedding of River Song", and also appears in "Closing Time". She later appears in "The Angels Take Manhattan" and "The Name of the Doctor".
^Coleman first appeared as Oswin Oswald in "Asylum of the Daleks", revealed in "The Name of the Doctor" to be one of multiple echoes of Clara distributed across time. In "The Snowmen", Coleman initially plays another echo of Clara, with her original iteration appearing briefly at the end of the episode. The latter Clara joins the Doctor permanently in "The Bells of Saint John".
^Clara continues traveling with the Doctor following his regeneration in "The Time of the Doctor".
^Clara dies in "Face the Raven" and appears only as an illusion in "Heaven Sent", before being temporarily rescued from death and appearing as a companion for the final time in "Hell Bent". She subsequently briefly appears in "Twice Upon a Time".
^Nardole first appears in "The Husbands of River Song" before appearing as a companion from "The Return of Doctor Mysterio".
^Nardole departs in "The Doctor Falls" before briefly reappearing in "Twice Upon a Time".
^Ann departs the Doctor in The Perfect Prisoners but re-appears in The Dalek Protocol (2021).
^Margaret first meets the Doctor in The Ravencliff Witch (2022) and later joins him as a companion in Ice Heist!
^Initially called Amy during her travels with the Doctor, she renames herself Abby before their reunion.
^Abby departs the Doctor in The Chaos Pool (2009) but re-appears in Wicked Sisters (2020).
^Frobisher departs the Sixth Doctor off-screen after The World Shapers, but they reunite in the graphic novel The Age of Chaos and the Big Finish Productions audio plays The Holy Terror and The Maltese Penguin.
^Evelyn's departure from the Sixth Doctor is depicted in flashbacks of Thicker than Water, where she reunites with the Sixth Doctor and new companion Mel. She re-appears with the Seventh Doctor in A Death in the Family (2010).
^Flip first meets the Doctor in The Crimes of Thomas Brewster (2011) and later joins him as a companion from The Curse of Davros to Scavenger (2014). She re-joins the Doctor and new companion Constance in Quicksilver (2016).
^Klein first meets the Doctor and Ace in Colditz (2001) and later joins him as a companion in A Thousand Tiny Wings.
^Klein travels with the Doctor from A Thousand Tiny Wings to The Architects of History (2010). A version of Klein from an alternative timeline meets the Doctor in UNIT: Dominion (2012), travels with him from Persuasion (2013) to Daleks Among Us, and encounters him again in Warlock's Cross (2018).
^Raine makes an earlier appearance in Thin Ice (2011) as a baby.
^Raine travels with the Doctor and Ace and departs off-screen after Earth Aid (2011). She returns as a companion without Ace in UNIT: Dominion.
^Sally departs in Afterlife (2013) and later appears in Signs and Wonders (2014).
^Molly departs the Doctor in Rule of the Eminence. An older version of Molly played by Sorcha Cusack re-appears in Master of the Daleks / Eye of Darkness (2015).
^Liv initially appears in Robophobia (2011) alongside the Seventh Doctor before joining the Eighth Doctor as a companion in The Traitor.
^In a flashforward in Best Day Ever, Liv is depicted as returning to Earth to live with Tania, though the circumstances of her departure is still unknown.
^Tom Price portrays the character in the Doctor Who spin-off series Torchwood and its corresponding spin-off media.
^Alex appears alongside the Eighth Doctor in An Earthly Child, Relative Dimensions, and Lucie Miller / To the Death (2010-2011). At the end of Restoration of the Daleks (2020), the Doctor encounters an alternate universe counterpart of Alex who joins him as a companion starting in Meanwhile, Elsewhere.
^Emma Campbell-Jones appears as Cass alongside the Eighth Doctor in the 2013 TV special mini-episode The Night of the Doctor where she apparently meets the Doctor for the first time, before both of them died in a crash. The Doctor encounters an earlier version of Cass during the Time War who joins him as a companion starting in Meanwhile, Elsewhere.
^Majenta initially appears in Hotel Historia before joining the Doctor as a companion in Thinktwice.
^After her departure in Dead-line, Heather makes a guest appearance in Lucky Heather.
^After his departure in Bad Wolfie, Wolfgang makes a guest appearance in Lucky Heather.
^Cindy appears in a number of issues as a friend of Gabby's starting from Revolutions of Terror until she finally joins as a companion in Arena of Fear.
^Anubis appears in a number of issues starting from Spiral Staircase until he finally joins as a companion in Breakfast at Tyranny's.
^The inclusion of Sara Kingdom as a companion varies; e.g. she does not appear on the BBC website list of companions. However, she is listed as a companion in many other sources.[39][40][41][42][43][44][45]
^Hayes, Paul (2023). Pull to Open: The Inside Story of How the BBC Created and Launched Doctor Who. Ten Acre Films. p. 145. ISBN978-1-908630-84-1. It's clear [from the initial planning document] that the Doctor is to be a mysterious character... It's made clear that, whatever the mystery of the Doctor is, it may well never be known to the viewers.
^Ainsworth, John, ed. (2015). Doctor Who: The Complete History: Volume 1. Panini UK/Hachette Partworks. p. 25. The old man would have a teenage girl companion for younger viewers to relate to, along with another couple between whom a romance could develop.
^ abBrook, Stephen (23 January 2009). "Michelle Ryan guest stars in Doctor Who. But would she make a good companion?". The Guardian. UK. Retrieved 1 June 2010. A minor factor in the continual swirl around Doctor Who is that what constitutes a Doctor Who companion is no longer clear. Sure, Rose, Martha, and Donna were all companions. So was Captain Jack. But what about Mickey and Jackie? How do you qualify? Name in the opening credits, regular trips in the Tardis? The Doctor kisses you? I'm no longer sure. Modern TV drama is so difficult.
^Sarah Jane Smith has appeared in "School Reunion", "The Stolen Earth", "Journey's End", and "The End of Time". K-9 has appeared in "School Reunion" and "Journey's End".
^Statement by Mickey Smith to Martha Smith-Jones in "The End of Time"
^Statement by Sarah Jane Smith to Luke Smith in the epilogue scene of Death of the Doctor part 2
^Doctor Who: Best of the Companions (Television production). BBC America. 28 August 2011.
^Gareth Roberts (24 September 2011). "Open All Hours". Doctor Who Confidential. Series 6. Episode 12. 4:52 minutes in. BBC. The Doctor allows Craig to come along and play the part of his companion [...]
