Companion Companions were the Doctor ' s closest friends . ( AUDIO : " Situation Vacant " , " No Place Like Home " ) Such people knew the Doctor ' s " secret " : that he was someone non - human who travelled in time and space in a police box - shaped craft called the TARDIS . They often directly saved his life ( TV : " Rose " , " The Family of Blood " ) or provided him with a perspective that prevented him from abusing his Time Lord powers . ( TV : " School Reunion " , " The Runaway Bride " , " The Fires of Pompeii " ) On some occasions , they were the proximate reason that the Doctor sacrificed his then - current life and regenerated . ( TV : " The Caves of Androzani " , " The Parting of the Ways " , " The End of Time " ) On others , they lost their lives in pursuit of the Doctor ' s goals . ( TV : " The Traitors " , " The Destruction of Time " , " Earthshock " , " Voyage of the Damned " , " Face the Raven " , AUDIO : " Absolution , " " To the Death " ) Because the term was a shortening of the expression " travelling companion " , most companions did in fact voyage with him in the TARDIS . Depending on the situation , other words were used to describe the same relationship — most frequently , " assistant " . However , it was unusual to hear the Doctor call his friends by " either " word . Different incarnations had different preferences . The Third Doctor , perhaps owing to his unique situation of exile , most frequently used the term " assistant " . ( TV : " The Ambassadors of Death " , " Terror of the Autons " ) On the other hand , when the Eighth Doctor was forced to define the word " companion " , he eschewed the term " assistant " in favour of " friend " . ( AUDIO : " Situation Vacant " ) Both terms were occasionally troublesome . Sometimes , the word " companion " was interpreted sexually , leading to confusion about the Doctor ' s relationship with his friends . ( TV : " Aliens of London " , " Closing Time " ) Sometimes , companions bickered over the appropriateness of the word " assistant " . Rose Tyler said emphatically , " I ' m not his assistant " , when Sarah Jane called her one . ( TV : " School Reunion " ) Rose seemed happier being called a " companion " , as when Harriet Jones called out over the Sub - Wave Network for " former companions of the Doctor " . ( TV : " The Stolen Earth " ) People were companions or assistants to the Doctor for varying lengths of time , but most stayed with him for more than one adventure . ( TV : " An Unearthly Child " , " The Daleks " , " The Rescue " , " The Romans " , " The Chase " , " The Time Meddler " et al . ) Some stayed for a few days , while others were with him for years . ( AUDIO : " No Place Like Home " ) Other Time Lord s , usually renegades , sometimes had travelling companions . Companions of the Doctor . Species and gender . Humans . In the main , the Doctor travelled with human s , some from the 20th and 21st centuries . ( TV : " An Unearthly Child " , " Bell of Doom " , " The War Machines " , " The Wheel in Space " , " Rose " , " Dalek " , " School Reunion " et al . ) His fondness for humans was one of the reasons he was exiled to Earth by the Time Lord s . ( TV : " The War Games " ) Amongst his human companions , he tended to prefer young women — a fact he once tried sheepishly to hide from Amy Pond . ( HOMEVID : " Meanwhile in the TARDIS " ) Despite the presence of many female companions , he usually had platonic relationships with them . However , there were exceptions . The relationship the Ninth and Tenth Doctor s had with Rose Tyler appeared romantic to other observers like Mickey Smith , ( TV : " Boom Town " , " School Reunion " , " Rise of the Cybermen " , " Doomsday " ) Martha Jones ( TV : " The Sound of Drums " ) and Donna Noble . ( TV : " Journey ' s End " ) His relationship with archaeologist s Bernice Summerfield and River Song were more explicitly romantic . Once on Epsilon Minima , Benny unexpectedly ran into the Eighth Doctor and recalled having sex with him soon after his regeneration . ( AUDIO : " Benny ' s Story " , PROSE : " The Dying Days " ) Similarly , his relationship with River , particularly in his eleventh incarnation , was overtly romantic — to the point that he ' married ' her in a ceremony that both parties seemed to accept as binding on some level . ( TV : " The Wedding of River Song " , " The Angels Take Manhattan " , HOMEVID : " Last Night " et al . ) Romantic feelings were not always reciprocated . Martha Jones was in love with the Doctor but was rebuffed . ( TV : " Last of the Time Lords " ) Equally , Amy Pond was sexually interested in the Doctor , but was firmly rejected . ( TV : " Flesh and Stone " ) Male humans . Because female humans were statistically more common , male human companions were exceptional . The Doctor ' s second incarnation was never long without a male assistant and then typically only after the Time Lord s forcibly removed Jamie McCrimmon from his side . ( COMIC : " at least " " Action in Exile " through " The Night Walkers " , but possibly all TVC Second Doctor stories ; PROSE : " World Game " , " Golem " , " Blue Road Dance " , " Scientific Adviser " , " That Time I Nearly Destroyed the World Whilst Looking for a Dress " , " Mother ' s Little Helper " , " Reunion " , " Dust " ) The Doctor ' s original incarnation " almost " always had a male companion after his introduction to Ian Chesterton . In fact , it was during his first life that the Doctor had multiple adventures " exclusively " with a male human , ( TV : " The Massacre of St Bartholomew ' s Eve " , PROSE : " Roses " , " Making History " , " Waiting for Jeremy " ) something that practically never happened thereafter . Still , it " did " happen , as when the Fifth Doctor adventured with a World War II American pilot , Gus . ( COMIC : " 4 - Dimensional Vistas - The Moderator " ) It may have happened with the Eighth Doctor ' s long - term companion , Fitz Kreiner . ( PROSE : " Escape Velocity " ) According to some accounts , the Doctor " also " travelled solo with Jamie McCrimmon some time after the Doctor ' s first Time Lord trial . However , during some of these adventures , the female companion was described as being temporarily left behind somewhere . ( AUDIO : " Helicon Prime " ) There were other accounts of the Doctor and Jamie travelling alone together , however , where no female companions were indicated . ( PROSE : " The Time Eater " , COMIC : " Invasion of the Quarks " to " Martha the Mechanical Housemaid " ) Nevertheless , it was extremely unclear how these stories " fit " into the same timestream as other established events . Later , the Third Doctor had several one - off adventures with human males who travelled in the TARDIS with him , including Charlie Fisher , ( COMIC : " Backtime " ) Finney , ( COMIC : " The Planet of the Daleks " ) Brod , ( COMIC : " A Stitch in Time " ) and Lammers . ( COMIC : " The Ugrakks " ) Another human male companion to travel alone and for more than one adventure with this particular Doctor was a boy named Arnold . ( COMIC : " Children of the Evil Eye " , " Nova " ) The Fifth Doctor had several adventures with the male Turlough after Tegan left , but before Peri arrived . However , Turlough wasn ' t human , but Trion . ( TV : " Planet of Fire " ) Likewise , the Sixth and Seventh Doctor s each had solo adventures with the male Frobisher , but he wasn ' t human and most of his " solo " adventures with the Doctor took place when Peri was temporarily in New York City . ( COMIC : " Kane ' s Story " ) The Eleventh Doctor briefly travelled with Rory as the only companion ; Rory ' s wife Amy was revealed to be a Ganger during their travels after the real Amy was abducted and taken to Demons Run . After the Doctor melted Ganger Amy into raw Flesh , the Doctor and Rory concentrated their efforts on locating the real Amy and recruiting an army to fight the kidnappers . ( TV : " The Almost People " , " A Good Man Goes to War " ) After spending 24 years with River Song on Darillium the Twelfth Doctor travelled with Nardole solo for a time . Their adventures included defeating Harmony Shoal . ( TV : " The Return of Doctor Mysterio " ) Non - humans . Despite a statistical preference for humans , the Doctor had non - human companions or at the very least , companions who were not from Earth or descended from its people , like Leela . On at least three occasions he travelled with members of his own species . The longest serving were his own granddaughter ( TV : " An Unearthly Child " , etc . ) and Romana II . ( TV : " Destiny of the Daleks " , etc . ) Lady Serena was significant as well , for sacrificing her life in service to the Doctor ' s goals . ( PROSE : " World Game " ) Other humanoid species with whom he adventured included , but certainly weren ' t limited to : Trakenite s , ( TV : " Logopolis " ) Alzarian s , ( TV : " Full Circle " ) Cyber - converted humans ( COMIC : " The Company of Thieves " ) and people from Sto . ( TV : " Voyage of the Damned " ) On occasion , he was accompanied by obviously non - human species , like Whifferdill s , ( COMIC : " The Shape Shifter " ) Ice Warrior s , ( COMIC : " Descendance " ) Oblivioner s , ( COMIC : " Bad Blood " ) Eutermesan s ( AUDIO : " The Creed of the Kromon " ) and Vessican s . ( COMIC : " Thinktwice " ) Artificial life - forms sometimes travelled with the Doctor , as well . Clearly , K9 was the Doctor ' s most - beloved robotic companion , given the number of models the Doctor built ( TV : " The Invasion of Time " , " School Reunion " , " A Girl ' s Best Friend " ) and the pleasure he displayed when he re - encountered a version of the robot . ( TV : " The Wedding of Sarah Jane Smith " ) The Doctor seemed empathetic to artificial life - forms with errors in their programming . He once effectively euthanised an android companion in irremediable distress . ( TV : " Planet of Fire " ) Shortly before his time on Trenzalore , the Eleventh Doctor obtained a Cyberman head he named " Handles " . Handles aided him greatly with technological assistance and was his only real companion during his first three hundred years on Trenzalore as he ' d sent Clara Oswald home and everyone he cared about that lived there eventually died . After three hundred years , Handles died of old age and it reduced the Doctor to tears . ( TV : " The Time of the Doctor " ) The Twelfth Doctor teamed up with a Dalek named Lumpy to collect the Orb of Fates and stop the Daleks , Cybermen and Sontaran s from controlling the " Starbane " . However it turned out that Lumpy had tricked the Doctor at the very beginning of the adventure . ( GAME : " The Doctor and the Dalek " ) His later companion , Nardole , was humanoid , but explicitly not human - he was at least partially cybernetic , ( TV : " The Pilot " ) harbored a distaste for humans , ( TV : " Smile " , " The Doctor Falls " ) and was only " human enough " because the Doctor had gotten his lungs cheap . ( TV : " The Pyramid at the End of the World " ) Comings and goings . Joining the Doctor . The Doctor began relationships with his companions in a great variety of ways . Some , like Adric , ( TV : " State of Decay " ) Leela , ( TV : " The Face of Evil " ) Tara , ( COMIC : " Official Secrets " ) and Zoe , ( TV : " The Wheel in Space " ) stowed away on the TARDIS , fully aware it was a ship that could take them away from their home . Others , like Ian Chesterton , Barbara Wright ( TV : " An Unearthly Child " ) and Dodo Chaplet , ( TV : " Bell of Doom " ) were taken away without their consent . He was also occasionally assigned assistants by those in nominal authority over him . During his exile on Earth , the Doctor ' s assistants were mostly supplied by the Brigadier . ( TV : " Spearhead from Space " , " Terror of the Autons " ) In the case of UNIT soldiers , the Doctor worked with whomever the Brigadier happened to have on duty at the time of a crisis . This was how he first met Mike Yates . ( PROSE : " The Eye of the Giant " ) The Doctor ' s " other " " bosses " — the Time Lord s ( PROSE : " World Game " , AUDIO : " Blood of the Daleks " ) and the White Guardian ( TV : " The Ribos Operation " ) — also occasionally provided companions , invariably against the Doctor ' s wishes . Even the Dalek s understood that he was commonly assisted by companions . For example , when the Daleks abducted the Eleventh Doctor for a mission regarding the Dalek Asylum , they also abducted his most recent companions , Amy Pond and Rory Williams , to assist him . ( TV : " Asylum of the Daleks " ) All that said , the most common way of initiating TARDIS travel was to be invited by the Doctor . Although with some cases there was , from their perspective , a significant gap of time between first meeting of the Doctor and getting to travel with him , Donna Noble , ( TV : " The Runaway Bride " , " Partners in Crime " ) Amy Pond ( TV : " The Eleventh Hour " ) and Rory Williams ( TV : " The Eleventh Hour " , " The Vampires of Venice " ) were companions who began travelling at the Doctor ' s request a significant amount of time after they first met . In most cases there was little to no time gap between meeting the Doctor and getting to travel with him , Clara Oswald , ( TV : " The Bells of Saint John " ) Martha Jones , ( TV : " Smith and Jones " ) Rose Tyler , ( TV : " Rose " ) Jack Harkness , ( TV : " The Doctor Dances " ) Ace , ( TV : " Dragonfire " ) Vislor Turlough , ( TV : " Mawdryn Undead " ) Izzy Sinclair , ( COMIC : " Endgame " ) Charley Pollard , ( AUDIO : " Storm Warning " ) Arnold , ( COMIC : " Children of the Evil Eye " ) Jamie McCrimmon , ( TV : " The Highlanders " ) Victoria Waterfield , ( TV : " The Evil of the Daleks " ) Vicki ( TV : " Desperate Measures " ) and others all began their travels with the Doctor because he asked them . Other companions " forced " their way into the TARDIS . Leela , despite the Fourth Doctor ' s protests , ran into the TARDIS and , before he could shoo her out , fiddled with the controls , causing it to dematerialise . ( TV : " The Face of Evil " ) Rarely , the Doctor invited people to travel with him , like Lynda Moss , ( TV : " The Parting of the Ways " ) Astrid Peth ( TV : " Voyage of the Damned " ) and Rita , ( TV : " The God Complex " ) only to have their death prevent their travels . The same thing happened with Clara Oswin Oswald , although the Doctor found out that there was another version of her somewhere in time and space and set out to find her . ( TV : " The Snowmen " ) Leaving the Doctor . People left the Doctor for reasons as varied as the reasons they first walked through the TARDIS doors . They were of three broad types : the companion wanted to leave ; ( TV : " The Planet of Decision " , " Horse of Destruction " , " The Savages " , " The War Machines " , " Last of the Time Lords " ) the Doctor wanted the companion to leave ; ( TV : " Flashpoint " , " The Long Game " , " Utopia " , " The God Complex " ) or some external force compelled the companion and Doctor to separate . ( TV : " The Traitors " , " The Destruction of Time " , " The War Games " , " The Hand of Fear " , " Earthshock " , " Doomsday " , " The Angels Take Manhattan " , " Hell Bent " ) When asked by Brian Williams , father to one of his companions , Rory Williams , and father - in - law to Amy Pond , another companion , what happened to the people who travelled with him , the Eleventh Doctor explained that some left him , some got left behind , and also admitted that " not many but some " died . ( TV : " The Power of Three " ) The companion ' s choice . The choice to leave was sometimes the companion ' s . A common reason for the departure of female human companions was romance . Sometimes , as with Vicki , ( TV : " Horse of Destruction " ) Jo ( TV : " The Green Death " ) and Leela , ( TV : " The Invasion of Time " ) they left to get married , while at least one companion , Martha Jones , left because she realised her romantic feelings for the Tenth Doctor would never be reciprocated . ( TV : " Last of the Time Lords " ) In the Doctor ' s youth , before he had established reasonable control over the TARDIS , companions sometimes left , at least in part , because they happened to have access to their own time period . This was especially true of the companions who had not actually " chosen " to travel with the Doctor , such as Ian and Barbara , ( TV : " The Planet of Decision " ) Dodo , ( TV : " The War Machines " ) , and Polly and Ben . ( TV : " The Faceless Ones " ) However , this sometimes happened later in the Doctor ' s life . Ly - Chee , for instance , thought the Seventh Doctor was only offering him a lift into town . Instead , they had several adventures together . When the TARDIS finally deposited him in the correct town , he headed for the nearest pub and ordered a stiff drink without once looking back . ( COMIC : " The Enlightenment of Ly - Chee the Wise " ) Some companions left to improve a particular society they had encountered with the Doctor . Nyssa left to help cure Lazar ' s disease ( TV : " Terminus " ) , whilst Steven Taylor stayed on the planet of the Elders to be its leader . ( TV : " The Savages " ) Likewise , Romana II chose to remain in E - Space to help the Tharil species . ( TV : " Warriors ' Gate " ) Tara Mishra left the Ninth Doctor after wishing to stay and help with the disaster aftermath on Nomicae , ( COMIC : " The Bidding War " ) though both parties made it explicit that this was temporary , and Jack Harkness was sent to collect her after some time . ( COMIC : " The Lost Dimension " ) Later , Mickey Smith deliberately stayed in the parallel Pete ' s World to help its citizens defeat the Cybermen . ( TV : " The Age of Steel " ) Mickey proved especially independent when it came to departing the Doctor ' s side ; he later left the TARDIS again , this time to return to his " home " Earth , ultimately to defend it from alien threats . ( TV : " Journey ' s End " , " The End of Time " ) Others left for more personal improvement . Melanie Bush parted ways from the Seventh Doctor purely to have new adventures in space — but not time — with Sabalom Glitz . ( TV : " Dragonfire " ) Frobisher left the Doctor to enjoy the pleasure planet A - Lux . ( COMIC : " A Cold Day in Hell ! " ) Liz Shaw left UNIT and the Third Doctor to return to her research , telling the Brigadier that all the Doctor needed in an assistant was " someone to pass him his test tubes and tell him how brilliant he was " . ( TV : " Terror of the Autons " ) After another brief adventure on Messaline Martha Jones declined to travel with the Doctor again wishing to be a part of UNIT . ( TV : " The Doctor ' s Daughter " ) Some companions left simply because they no longer enjoyed travelling with the Doctor . Victoria Waterfield left because she had grown tired of the continual danger in which she found herself and decided to choose a safer new life . ( TV : " Fury from the Deep " ) Tegan Jovanka similarly left because she had become sickened by the death and destruction she witnessed . ( TV : " Resurrection of the Daleks " ) Because they were Earth - based assistants who either never wanted to travel with the Doctor on a long - term basis or never were invited to do so , a few companions made only a single journey or two , but otherwise provided significant assistance from Earth . The Brigadier ( TV : " The Invasion " , " The Five Doctors " ) and Wilfred Mott ( TV : " The Stolen Earth " , " The End of Time " ) were classic examples of this sort of assistant , but Maxwell Edison ( COMIC : " Stars Fell on Stockbridge " ) and , for a time , Mickey Smith ( TV : " Aliens of London " / " World War Three " , " School Reunion " , " The Girl in the Fireplace " ) could be viewed in this light as well . Harry Sullivan also left the Doctor to return to his usual life after a single trip in the TARDIS ( TV : " Terror of the Zygons " ) , albeit one punctuated by several detours by other means . One companion who briefly left by her choice was Clara Oswald . After a trip to the Moon in which she was forced to decide whether to kill an innocent creature or not and the Twelfth Doctor refused to help , Clara grew so angry she left the TARDIS , telling the Doctor never to come find her again . ( TV : " Kill the Moon " ) However , with the help of Danny Pink , she realised she wasn ' t ready to give up the Doctor yet and agreed to a final trip with him weeks later to the " Orient Express " at which point she decided to permanently rejoin him despite the dangers and the coldness the Doctor once again displayed on the trip . ( TV : " Mummy on the Orient Express " ) Clara again left the TARDIS after Danny ' s death , under the mistaken belief that the Doctor had found his home planet of Gallifrey , while the Doctor believed that Danny was alive and with Clara . ( TV : " Death in Heaven " ) Later , the Doctor returned to save her life , in an adventure in which both lies were exposed . Afterwards , the Doctor gave Clara one more invitation to join him again , and she accepted . ( TV : " Last Christmas " ) The Doctor ' s choice . Sometimes companions were kicked out of the TARDIS , either as punishment or for the companion ' s personal growth . Adam Mitchell was summarily tossed out after he was found trying to use his trip into the future to alter his own fortunes . ( TV : " The Long Game " ) Susan , ( TV : " Flashpoint " ) Arnold , ( COMIC : " The Amateur " ) John and Gillian ( COMIC : " Invasion of the Quarks " ) were more charitably dismissed . The Doctor clearly believed he was doing them good by ending their travels . The Doctor prevented these youths from continuing to travel with him because he felt it would interfere with their natural maturation . Married couple Amy and Rory were returned home by the Eleventh Doctor , who feared for their lives if they continued on their travels . ( TV : " The God Complex " ) The Twelfth Doctor left Clara Oswald home after believing she ' d gotten her dead boyfriend Danny Pink back from the Nethersphere and would be happy with him . ( TV : " Death in Heaven " ) Separation by situation . There were occasions when the Doctor and his companions were separated more by circumstance than the wishes of either party . Perhaps the most obvious case of this was when the Tenth Doctor and Rose Tyler were separated by the closure of the walls between dimension s . ( TV : " Doomsday " ) Sarah Jane Smith ' s departure occurred because the Fourth Doctor was summoned to Gallifrey ( TV : " The Hand of Fear " ) at a moment in Gallifreyan history when human s weren ' t allowed on the planet . ( TV : " School Reunion " ) The Time Lords forced Zoe and Jamie to part from the Second Doctor , with only the memories of their first adventure with him intact . ( TV : " The War Games " ) The Time Lords later claimed they had developed this procedure into a " standard response " for companions with whom they dealt . The Sixth Doctor , for instance , encountered a version of Peri Brown who had been given " the Jamie and Zoe treatment " . She retained memories only of the adventure with the Fifth Doctor , Turlough and which began on Lanzarote . ( AUDIO : " Peri and the Piscon Paradox " ) Finally , whilst in his tenth body , the Doctor had to stabilise the effects of a biologically untenable combination of his DNA with Donna Noble ' s . To do so , he had to submerge all memories of her time with him and shield her from those memories lest she die . Thus , although he did , in a sense , kick her out of the TARDIS for her own good , neither wanted it . ( TV : " Journey ' s End " ) She did briefly remember of her travels , but was knocked unconscious by it and then forgot again . ( TV : " The End of Time " ) Similarly , Donna ' s consciousnesses was saved to The Library against her will causing her to forget about the Doctor and spending years from her point of view married to Lee McAvoy . This was only temporary , however , and soon afterwards she resumed her travels . ( TV : " Silence in the Library " / " Forest of the Dead " ) Jack Harkness ' days in the TARDIS came to an end in similarly unusual circumstances . Because he had died and been resurrected by Rose as the Bad Wolf entity , he became , in the words of the Tenth Doctor " just wrong " . No longer able to die , he was instead a kind of " fixed point in time " which the TARDIS herself rejected . ( TV : " Utopia " ) Nevertheless , the Doctor re - invited him on board the TARDIS ( TV : " Last of the Time Lords " ) and he later travelled aboard it without apparent difficulty . ( TV : " Journey ' s End " ) However , on both occasions , he was more interested in pursuing a life with Torchwood Three than returning to the Doctor ' s side on a long - term basis . Amy Pond and Rory Williams were sent back in time by a Weeping Angel , separating them from the Eleventh Doctor for the remainder of their lives . They both died at age 87 and 82 respectively . ( TV : " The Angels Take Manhattan " ) Death . Some companions died , often in service to the Doctor ' s goals . Katarina ( TV : " The Traitors " ) and Sara Kingdom ( TV : " The Destruction of Time " ) both died to prevent the Dalek s obtaining taranium . Adric sacrificed himself trying to stop a prehistoric Cyberman invasion of Earth . ( TV : " Earthshock " ) Roz Forrester died in battle . ( PROSE : " So Vile a Sin " ) Lucie Miller and Tamsin Drew were both killed whilst defeating the Dalek Time Controller ' s invasion of Earth in the late 22nd century . ( AUDIO : " To the Death " ) Astrid Peth died killing Max Capricorn . Her atoms were left to travel the universe . Without her sacrifice , the Tenth Doctor would not have regained control of the " Titanic " , nor prevented it from having a costly collision into Buckingham Palace . ( TV : " Voyage of the Damned " , " Turn Left " ) Three unusual cases were those of Peri Brown , Ace and River Song . Peri was killed by King Yrcanos on Thoros Beta , whilst her body was being subjected to Crozier ' s troubling body - swapping experimentations . For a time , the Sixth Doctor believed Peri had died . At the conclusion of his second major trial by the Time Lord s , however , the Inquisitor revealed Peri ' s death had likely been a trick of the Valeyard . The Inquisitor showed the Doctor that Peri , far from being killed by Yrcanos , had , in fact , married him . ( TV : " Mindwarp " ) However , at a later date , the Time Lords revealed their meddling with Peri ' s timestreams had resulted in multiple versions of Peri running around the cosmos . One of these Peris had been killed by Yrcanos , as the Doctor originally believed . ( AUDIO : " Peri and the Piscon Paradox " ) Like Peri , Ace died young according to two accounts , but not others . According to one , she died while using Nitro - 9 against parasitic beings known as the Lobri . Her sacrifice saved the lives of Sarah Jane , Susan , Peri and the Seventh Doctor . ( COMIC : " Ground Zero " ) In another account she was killed by George Limb , only to be replaced by a divergent version of herself , who continued to travel with the Doctor and who only had superficial differences from her other self . ( PROSE : " Loving the Alien " ) Furthermore , according to other accounts , she lived to a much older age — at least into her late thirties . ( PROSE : " Set Piece " , amongst others ) Cinder , who was briefly a companion of the War Doctor , sacrificed her life to save the Doctor when the Time Lord Karlax tried to kill him under orders from Rassilon . It was for fear of this highly probable eventuality of a companion ' s death that the War Doctor was reluctant to let a companion join him during his years of fighting in the Last Great Time War . He gave Cinder a proper burial and promised to end the Time War to honour her sacrifice . ( PROSE : " Engines of War " ) River Song died physically when she linked her mind into the CAL computer during the Doctor ' s first meeting with her - - from his perspective ; from hers , it was the last of many following an unspecified period of time as his companion . ( TV : " Forest of the Dead " ) Unknown to the Tenth Doctor , River was part Time Lord due to having been conceived on board the TARDIS by the Doctor ' s future companions Amy Pond and Rory Williams , but had given up her future regenerations to save the Eleventh Doctor ' s life . ( TV : " A Good Man Goes to War " , " Let ' s Kill Hitler " ) The Doctor , therefore , proceeded with his timeline knowing how River would one day die . He gave her a sonic screwdriver specially designed to save her mental patterns at the moment of her death in the Library . ( TV : " The Husbands of River Song " ) This allowed the earlier Tenth Doctor to upload River into CAL ' s immense memory bank , allowing her to live on in the computer . ( TV : " Forest of the Dead " ) She later managed to somehow link herself into a psychic " conference call " from inside CAL even as a data ghost to aid the Doctor one last time on Trenzalore before fading forever after he finally said goodbye to her . ( TV : " The Name of the Doctor " ) Kamelion , an android companion , was destroyed by the Fifth Doctor in an act of mercy per Kamelion ' s own request after it was taken over by . ( TV : " Planet of Fire " ) Clara Oswald , a companion of the Eleventh and Twelfth Doctor s , sacrificed herself for Rigsy , whom she had only met once before . She was killed by a Quantum Shade after saying goodbye to the Time Lord , with the Doctor ultimately blaming Ashildr for her death . ( TV : " Face the Raven " ) The Twelfth Doctor extracted her from her timestream moments before her death using Time Lord technology , although she was frozen in between one heartbeat and her last . He realised that they couldn ' t continue travelling together as the prophecies of the Hybrid would come to pass , so he planned to erase Clara ' s memories of him with a neural block . However , upon discovering this , Clara attempted to reverse the polarity of the neural block so it would affect the Doctor , something he doubted had worked when she told him . They agreed to activate the device together , not knowing which one of them would be affected , and it affected the Doctor . Clara left in a stolen TARDIS with Ashildr to travel the universe before returning to Gallifrey and dying . ( TV : " Hell Bent " ) Unknown reasons . Very rarely , it was unknown what caused certain companions to stop travelling with the Doctor . This was true of Destrii . In the case of the Earthbound Third Doctor , relationship timings with his occasional assistants became very unclear . Assistants in this period didn ' t " stop " travelling with him ; his exile on Earth made it impossible for them to " start " travelling with him . ( TV : " Spearhead from Space " - " The Three Doctors " ) Assistants during this period tended to be people who lived in England ( TV : " Spearhead from Space " , " Terror of the Autons " ) whom he could meet in Bessie . Since he wasn ' t housing companions in the TARDIS , there wasn ' t a definite " moment " when an assistant entered or left " the TARDIS team " . Therefore , incomplete records existed as to how long the Doctor knew certain assistants . It was never known , for example , definitively when the Doctor met or said goodbye to Tom Phipps and Joe . ( COMIC : " The Vortex " , " Fogbound " ) The influence of Gallifrey . The Fourth Doctor lost four consecutive companions to the direct or indirect influence of Gallifrey : he was forced to leave Sarah Jane Smith on Earth on receiving an emergency summons ; ( TV : " The Hand of Fear " ) Leela and K9 Mark I chose to stay on Gallifrey ; ( TV : " The Invasion of Time " ) and Romana II , who had been summoned to return to Gallifrey ( TV : " Full Circle " ) escaped by remaining in E - Space with K9 Mark II . ( TV : " Warriors ' Gate " ) The Sixth Doctor was also unable to save Peri Brown , being transported away by the Time Lords at a crucial moment . ( TV : " Mindwarp " ) Companions of other Time Lords . Other Time Lord s had companions in their travels . Before his final corruption into the renegade known as the Master , the Time Lord Koschei was accompanied in his hunt for the Doctor by Ailla . Koschei believed Ailla a young woman from a 28th century Earth colony , but she was in fact a Time Lady agent sent by the High Council to spy on his increasingly erratic behaviour . ( PROSE : " The Dark Path " ) In his battle with the newly regenerated Eighth Doctor , the Master was assisted by Chang Lee , a young man in 1999 San Francisco . Lee had been convinced by the Master that the Doctor was evil . Only too late did he learn the truth when the Master killed the boy , although the TARDIS subsequently restored him to life . ( TV : " Doctor Who " ) The Master during the Time War , took on Cole Jarnish as a companion . ( AUDIO : " The Good Master " ) However , this was nothing more than a ruse and he killed him once his usefulness had come to an end . ( AUDIO : " The Heavenly Paradigm " ) , the Master worked with Chantho , who in many ways could be considered his companion . However , after regaining memories of his previous incarnations , the Master killed Chantho . ( TV : " Utopia " ) As part of a test of the Missy incarnation of the Master ' s redeemed goodness , the Twelfth Doctor sent her on a mission with his own companions Bill Potts and Nardole acting as Missy ' s companions . ( TV : " World Enough and Time " ) The Time Lady known to the Doctor as Iris Wildthyme had several companions such as Timmy , Panda and . ( PROSE : " The Scarlet Empress " ) When she left the Fourth Doctor in E - Space , Romana II was accompanied by K9 Mark II . ( TV : " Warriors ' Gate " ) K9 continued as her companion after she returned to Normal Space . ( WC : " Shada " , et al . ) After returning to Gallifrey , Romana shared numerous adventures alongside one of the Doctor ' s former companions , Leela . ( AUDIO : " Gallifrey " ) Some time after leaving the Doctor , Lucie Miller travelled with the Monk , apparently after responding to an ad he placed in 2010 for a companion . ( AUDIO : " Situation Vacant " ) He later abandoned her , convincing Tamsin Drew , the Doctor ' s current companion , to join him instead . ( AUDIO : " The Resurrection of Mars " ) During the War , it became commonplace for Time Lords to take their humanoid type 103 TARDIS es as companions ; ( PROSE : " Alien Bodies " ) equally , from another point of view , the time ships were taking their pilots as companions . ( PROSE : " The Book of the War " ) Homunculette travelled with Marie in this way . ( PROSE : " Alien Bodies " ) Companions of non - Time Lords . After being cut off from the caldera , the 102 - form timeship Compassion had multiple time sensitive companions to act as her power source . ( PROSE : " Warring States " ) These included the Gallifreyan technician Nivet , ( PROSE : " The Ancestor Cell " ) Carmen Yeh , ( PROSE : " The Book of the War " ) and Octavia Sutherland . ( PROSE : " Warring States " ) When Elizabeth Klein rewrote history using the Doctor ' s stolen TARDIS to ensure the existence of the Third Reich into the future , she was given the position of head of Temporal Affairs . In this capacity , she travelled in the TARDIS with Major Richter , although it was an open secret that he was there to both learn how to use the TARDIS himself and ensure that Klein ' s loyalties remained with the Reich rather than risk her sympathizing with the aliens she encountered ( AUDIO : " The Architects of History " ) . Jackson Lake , while believing himself to be the Doctor , had Rosita as his companion . In fact the real Doctor , in his tenth incarnation initially considered " himself " to be Jackson ' s companion . Rosita continued as Jackson ' s companion even after his memory and original personality were restored , being hired by Jackson to act as the nursemaid for his son Frederic Lake . ( TV : " The Next Doctor " ) Jack Harkness compared his relationship with Angelo Colasanto to that of the Doctor and his companions . ( TV : " Immortal Sins " ) Later in his timeline , Jack ' s relationship with Gwen Cooper as he took her under his wing to introduce her to Torchwood also had a Doctor - companion undertone . ( TV : " Everything Changes " ) Sarah Jane Smith developed her own cohort of companions during her time based out of 13 Bannerman Road . These were her adopted children Luke ( TV : " Invasion of the Bane " ) and Sky ( TV : " Sky " ) and several local teenagers who came and went over time : Maria Jackson , ( TV : " Invasion of the Bane " , " The Last Sontaran " ) Clyde Langer , ( TV : " Revenge of the Slitheen " ) Rani Chandra ( TV : " The Day of the Clown " ) and Kelsey Hooper . ( TV : " Invasion of the Bane " ) She also had two non - human companions : K9 Mark IV and the alien supercomputer Mr Smith . ( TV : " Invasion of the Bane " ) Behind the scenes . What does the word " companion " actually mean ? The term " companion " is used more outside the programme — which is to say in fandom — than within the narrative . It was especially rarely used in the original version of the television programme and practically never uttered by the Doctor himself until the John Nathan - Turner producer ship . " Assistant " was a far more common designation — being used , for instance , by the First Doctor to describe Dodo Chaplet in " The War Machines " , by the Brigadier to introduce Jo Grant in " Terror of the Autons " and by the Fifth Doctor to jog the Brig ' s memory of Jo in " Mawdryn Undead " . However , " companion " has been heard with greater regularity in other media — particularly that written since the transmission of " Survival " . Indeed , Big Finish Productions have an entire range of product called " The Companion Chronicles " , which focusses on telling " Doctor Who " adventures from the perspective of the assistant . Equally , " Doctor Who Magazine " have taken to labelling the role that of " companion " — as they did on the cover of DWM 446 , when they announced the arrival of Jenna - Louise Coleman . The tacit assumption between " DWM " editors and their readers is that , somehow , both groups know what the other is talking about — as if the word " companion " were a title whose qualifications and responsibilities were well defined . However , this is not the case . Neither " assistant " nor " companion " have ever been unambiguously defined in a narrative . Without a solid in - universe definition , viewers are left to struggle with the term on their own . At what point , they are forced to ask themselves , does a supporting character become a " companion " ? Is it when they travel in the TARDIS ? If so , then Liz Shaw isn ' t a companion , despite being the clear co - star of an entire season . Is it when they ' re in more than one story ? If so , then Sara Kingdom , Christina de Souza , Jackson Lake , Adelaide Brooke , Wilfred Mott and Astrid Peth must be struck from the list , despite the fact that their respective actors were given star billing in their respective episodes ( Kingdom excluded as she was featured in a 1960s story , long before " star billing " ) . Can Jackie Tyler be considered a companion , since she appeared in numerous stories " and " she travelled in the TARDIS , " and " she even helped the Doctor recover after a regeneration ? Meta - fictional and story considerations are also a problem . Canton Everett Delaware III spent three months assisting the Doctor , travelled in the TARDIS at least once , and encountered him again forty years later , yet lack of star billing and the fact his time with the Doctor is shown over only two episodes puts his status in dispute . Then there are behind - the - scenes concerns . If an actor like Jean Marsh tells us flatly that she was not hired as a companion ( BFX : " The Drowned World " , DOC : " From Kingdom to Queen " ) and the official BBC website ' s own list of companions does not include her , is it reasonable to consider Sara Kingdom a companion ? If her , why not Bret Vyon , who also appeared in several episodes of TV : " The Daleks ' Master Plan " fulfilling a function nearly identical to Sara ? In a similar vein , the early story TV : " The Keys of Marinus " features two characters , Altos and Sabetha , who non - ambiguously joined the TARDIS crew as companions for the course of the single adventure , although they never rode in the TARDIS itself ; do they have as valid a claim to being companions as Christina de Souza , who likewise never set foot in the TARDIS during her single adventure ? This question can be expanded to the literally hundreds of characters depicted on TV , in comic strips and in literature who over the years have filled companion - like roles in one - off stories as they encountered the Doctor . Indeed some of these characters have been promoted to ersatz companion status . For a time , Henry Gordon Jago and George Litefoot could be described as just this ; one - off characters from TV : " The Talons of Weng - Chiang " who decades later , were featured in an edition of the Big Finish Productions audio series , " The Companion Chronicles " , and later given their own spin - off series . However they travelled with the Sixth Doctor in AUDIO : " Voyage to Venus " and " Voyage to the New World " , making their status as companions less controversial . All these question marks ! Determining who is a companion and who is not is one of the most common fan debates . It is possible by the fact that the television programme itself offers no definition for the term . Though probably exacerbated by the BBC Wales version ' s greater narrative flexibility , the debate is hardly a new one . It ' s been going on for ages , fuelled in previous decades by officially licensed reference works that helped mould fan opinion . For instance , the Brigadier , one of the people whose companion status is most hotly contested , gets some support for his alleged " companion status " from the book " The Making of Doctor Who " , in which two of the main writers of his era of the programme unambiguously called him a companion . Likewise , the later John Nathan - Turner book , " The Companions " was influential in making 1980s fans remember Sara Kingdom and for enshrining her as a companion — albeit against evidence in the BBC archives . Still , though the new series put the " term " " companion " on more solid narrative ground — even two British Prime Minister s had used it by the end of the RTD era — it greatly confuses the definition . In truth , though , it ' s " never " been very clear , even from a behind - the - scenes perspective . Though BBC Wales have confused things by putting single - episode guest stars in the opening credits , the " classic " series sowed similar confusion by often not listing " companions " very high in the credit list . Any definition of " companion " as " co - star " falls apart in the classic era , because companions were often listed " after " guest stars — sometimes after " several " guest stars . And claims that they were " regulars " must be counterbalanced against the fact that they were often contracted only for a matter of weeks , and lived under the threat of being unceremoniously dismissed mid - serial , like Jackie Lane was . Term as used on this wiki . This narrative uncertainty makes it difficult for " this wiki " to consistently use the term . Several forum debates have raged as to how the term should be applied , including and . Those readers wishing to understand why certain companions are included on certain lists that appear on this site may want to explore those discussions . Televised longevity . In televised " Doctor Who " , actors who played companions rarely stayed more than a series . Though some companions had notably long runs , they were the exception more than the rule . Discounting companions like Astrid Peth and Sara Kingdom — each of whom appeared in only a single story — the record - holder for shortest run would be Adam Mitchell . He appeared in only two stories or about 90 minutes of televised " Doctor Who " , spread across eight days of real - world time . Record - holders for " longest " tenures can be measured in different ways .