Editing UNIT (section)

== Main characters ==
* [[The Doctor (Doctor Who)|The Doctor]] has been UNIT's principal scientific advisor since their [[Third Doctor|third incarnation]] was exiled to Earth (having previously collaborated with UNIT during their [[Second Doctor|second incarnation]]).<ref name="the invasion2">{{cite serial|title=The Invasion|title-link=The Invasion (Doctor Who)|series=Doctor Who|series-link=Doctor Who|first=Derrick (writer)|last=Sherwin|author-link=Derrick Sherwin|first2=Douglas (director)|last2=Camfield|author-link2=Douglas Camfield|network=[[BBC]]|station=[[BBC1]]|date=2 November – 21 December 1968}}</ref><ref name="the three doctors2">{{cite serial|title=The Three Doctors|title-link=The Three Doctors (Doctor Who)|series=Doctor Who|series-link=Doctor Who|first=Bob|last=Baker|author-link=Bob Baker (scriptwriter)|first2=Dave (writers)|last2=Martin|author-link2=Dave Martin (screenwriter)|first3=Lennie (director)|last3=Mayne|author-link3=Lennie Mayne|network=[[BBC]]|station=[[BBC1]]|date=30 December 1972 }}</ref> The Doctor departed from UNIT's full-time employment during their [[Fourth Doctor|fourth incarnation]],<ref>{{cite serial|title=Pyramids of Mars|title-link=Pyramids of Mars|series=Doctor Who|series-link=Doctor Who|first=Stephen (writer)|last=Harris|author-link=Robert Holmes (scriptwriter)|first2=Paddy (director)|last2=Russell|author-link2=Paddy Russell|network=[[BBC]]|station=[[BBC1]]|date=25 October – 15 November 1975}}</ref> leaving a space-time telegraph<ref>{{cite serial|title=Revenge of the Cybermen|title-link=Revenge of the Cybermen|series=Doctor Who|series-link=Doctor Who|first=Gerry (writer)|last=Davis|author-link=Gerry Davis (screenwriter)|first2=Michael E. (director)|last2=Briant|author-link2=Michael E. Briant|network=[[BBC]]|station=[[BBC1]]|date=19 April – 10 May 1975}}</ref> (and, later, the TARDIS's telephone number)<ref name="the sontaran stratagem3">{{Cite episode |title=The Sontaran Stratagem |episode-link=The Sontaran Stratagem |series=Doctor Who |series-link=Doctor Who |first=Helen (writer) |last=Raynor |author-link=Helen Raynor |first2=Douglas (director) |last2=Mackinnon |author-link2=Douglas Mackinnon |network=[[BBC]] |station=[[BBC One]] |date=26 April 2008 |series-no=4 |number=4}}</ref> with which they could be summoned in emergencies. They retain their credentials, still bearing their third incarnation's portrait;<ref name="battlefield3">{{cite serial|title=Battlefield|title-link=Battlefield (Doctor Who)|series=Doctor Who|series-link=Doctor Who|first=Ben (writer)|last=Aaronovitch|author-link=Ben Aaronovitch|first2=Michael (director)|last2=Kerrigan|author-link2=Michael Kerrigan|network=[[BBC]]|station=[[BBC1]]|date=6–27 September 1989}}</ref> and, initially, UNIT personnel [[Harry Sullivan (Doctor Who)|Surgeon-Lieutenant Harry Sullivan]] and [[Sarah Jane Smith]] as their [[Companion (Doctor Who)|companions]]. Despite the looseness of their UNIT affiliation and their frequent disagreements with the organization, The Doctor continues to consider UNIT's scientific advisor to be their job, even into their [[Thirteenth Doctor|thirteenth]], fourteenth and fifteenth incarnations.
* [[Brigadier Lethbridge-Stewart|Brigadier Alistair Gordon Lethbridge-Stewart]] (later Sir Alistair Gordon Lethbridge-Stewart) is a founder of UNIT and the original commander of its British contingent. During the Third Doctor's exile on Earth, he hires the Doctor as his scientific advisor. He was the father of Kate Lethbridge-Stewart, another UNIT commander.<ref name="the power of three2">{{Cite episode |title=The Power of Three |episode-link=The Power of Three (Doctor Who) |series=Doctor Who |series-link=Doctor Who |first=Chris (writer) |last=Chibnall |author-link=Chris Chibnall |first2=Douglas (director) |last2=Mackinnon |author-link2=Douglas Mackinnon |network=[[BBC]] |station=[[BBC One]] |date=22 September 2012 |series-no=7 |number=4}}</ref>
* Sergeant Benton first appears as Corporal Benton in ''[[The Invasion (Doctor Who)|The Invasion]]'' and becomes a regular fixture of UNIT stories from ''[[The Ambassadors of Death]]'' until ''[[The Android Invasion]]''. In his final three appearances, during the Fourth Doctor era, he has been promoted to [[regimental sergeant major]].
* [[Liz Shaw]], originally drafted from the [[University of Cambridge]] as UNIT's scientific advisor, first appears in ''[[Spearhead from Space]]'' and accepts the position of the Third Doctor's assistant when he takes the job of scientific advisor.<ref>{{Cite web |title=Liz Shaw {{!}} Doctor Who {{!}} Doctor Who |url=https://www.doctorwho.tv/characters/liz-shaw |access-date=2022-09-25 |website=www.doctorwho.tv |language=en}}</ref>
* [[Jo Grant]] is a civilian employee of UNIT who was assigned as assistant to the Third Doctor, replacing Liz Shaw. The character appears from the serial ''[[Terror of the Autons]]'' in 1971<ref name="terror of the autons2">{{cite serial|title=Terror of the Autons|title-link=Terror of the Autons|series=Doctor Who|series-link=Doctor Who|first=Robert (writer)|last=Holmes|author-link=Robert Holmes (scriptwriter)|first2=Barry (producer)|last2=Letts|author-link2=Barry Letts|network=[[BBC]]|station=[[BBC1]]|date=2–23 January 1971}}</ref> until ''[[The Green Death]]'' in 1973.<ref name="the green death">{{cite serial|title=The Green Death|title-link=The Green Death|series=Doctor Who|series-link=Doctor Who|first=Robert (writer)|last=Sloman|author-link=Robert Sloman|first2=Michael E. (director)|last2=Briant|author-link2=Michael E. Briant|network=[[BBC]]|station=[[BBC1]]|date=19 May – 23 June 1973}}</ref> According to the novelisation of ''Terror of the Autons'', she holds the rank of Corporal.
* Captain Mike Yates also makes his first appearance in ''Terror of the Autons'' and appears regularly throughout the Third Doctor era. He is an officer who mainly serves as Brigadier Lethbridge-Stewart's adjutant.
* [[Sarah Jane Smith]] is an [[Investigative journalism|investigative journalist]] who becomes a UNIT associate by way of her companion relationship with the Third, Fourth, [[Tenth Doctor|Tenth]] and [[Eleventh Doctor|Eleventh]] [[The Doctor (Doctor Who)|Doctors]]. Sarah Jane maintains contact with, and receives support from, senior UNIT personnel throughout her lifetime.<ref name="death of the doctor2">{{cite serial|title=Death of the Doctor|title-link=Death of the Doctor|series=The Sarah Jane Adventures|series-link=The Sarah Jane Adventures|first=Russell T (writer)|last=Davies|author-link=Russell T Davies|first2=Ashley (director)|last2=Way|author-link2=Ashley Way|network=[[CBBC (TV channel)|CBBC]]|date=25–26 October 2010}}</ref><ref>{{cite serial|title=The Lost Boy|title-link=The Lost Boy (The Sarah Jane Adventures)|series=The Sarah Jane Adventures|series-link=The Sarah Jane Adventures|first=Phil (writer)|last=Ford|author-link=Phil Ford (writer)|first2=Charles (director)|last2=Martin|author-link2=Charles Martin (director)|network=[[CBBC (TV channel)|CBBC]]|date=12–19 November 2007}}</ref>
* [[Harry Sullivan (Doctor Who)|Harry Sullivan]], a Surgeon-Lieutenant in the Royal Navy, is a medical officer in UNIT at the time of the Doctor's third regeneration and becomes his companion for several adventures.
* {{anchor|Osgood|Petronella Osgood}} Petronella Osgood, played by [[Ingrid Oliver]], is a UNIT scientist and assistant to Kate Stewart in "[[The Day of the Doctor]]" (2013). She wears a long, knitted scarf of many colours, reminiscent of the [[Fourth Doctor]]'s scarf, and suffers from a respiratory ailment for which she uses an inhaler when over-excited. In "The Day of the Doctor", she comes to be impersonated by a Zygon, and the two get along rather well.<ref name="The Day of the Doctor">{{Cite episode |title=The Day of the Doctor |episode-link=The Day of the Doctor |series=Doctor Who |series-link=Doctor Who |first=Steven (writer) |last=Moffat |author-link=Steven Moffat |first2=Nick (director) |last2=Hurran |author-link2=Nick Hurran |network=[[BBC]] |station=[[BBC One]] |date=23 November 2013}}</ref> Following a peace treaty between humans and Zygons, which resulted in 20 million Zygons settling on earth disguised as humans, the Zygon duplicate remains in the form of Osgood, with neither version of Osgood revealing to others which is which. One version of Osgood works with Kate Stewart and the [[Twelfth Doctor]], in the episode "[[Death in Heaven]]" (2014), wearing a [[bow tie]] reminiscent of the [[Eleventh Doctor]] and [[Chuck Taylor All-Stars|Converse]] reminiscent of the [[Tenth Doctor]]. She is shown to be eager to please the Doctor and admires him. The Doctor hints that he might consider making her a companion, but she is disintegrated by [[Master (Doctor Who)#Missy|Missy]]. Osgood displayed a great deal of self-control as she near-calmly tried persuading Missy to spare her with logical explanations.<ref name="death in heaven">{{Cite episode |title=Death in Heaven |episode-link=Death in Heaven |series=Doctor Who |series-link=Doctor Who |first=Steven (writer) |last=Moffat |author-link=Steven Moffat |first2=Rachel (director) |last2=Talalay |author-link2=Rachel Talalay |network=[[BBC]] |station=[[BBC One]] |date=8 November 2014 |series-no=8 |number=12}}</ref> In "[[The Zygon Invasion]]" (2015), the surviving Osgood is kidnapped by a splinter group of Zygons led by Bonnie, who seeks war with the humans. After being rescued by the Doctor, she travels with him to UNIT Black Archive in an attempt to keep the peace while refusing to tell him whether she is human or Zygon. In "[[The Zygon Inversion]]", the Doctor, after successfully convincing Bonnie to live peacefully with humanity, offers Osgood a trip in the TARDIS. Osgood refuses, revealing Bonnie has become her new duplicate.
* [[Martha Jones]], codename "Greyhound 6", becomes a medical doctor after her adventures with the Doctor, and subsequently a Medical Officer for UNIT. She contacts the Doctor so he could help UNIT in the episode "[[The Sontaran Stratagem]]" (2008).<ref name="the sontaran stratagem3"/> She becomes trusted enough in UNIT to be given the Osterhagen Key, part of a mechanism for a program to destroy Earth.
* [[Kate Lethbridge-Stewart]], also known as Kate Stewart, is the Commander in Chief of UNIT; formerly the Chief Scientific Officer and ''de facto'' leader of UNIT's UK contingent in the 2010s and 2020s. She first appears in "[[The Power of Three (Doctor Who)|The Power of Three]]" (2012), introduced by [[Chris Chibnall]], before returning in the fiftieth anniversary special "[[The Day of the Doctor]]" (2013) and subsequently recurring during the [[Twelfth Doctor|Twelfth]], [[Thirteenth Doctor|Thirteenth]], [[Fourteenth Doctor|Fourteenth]] and [[Fifteenth Doctor]]'s eras. Kate is the daughter of Brigadier Lethbridge-Stewart. The character was created for the unofficial spin-off videos ''[[Downtime (Doctor Who)|Downtime]]'' (1995) and ''[[Dæmos Rising]]'' (2004), in which she was played by [[Beverley Cressman]]. She is depicted as a single mother to Gordon Lethbridge-Stewart, who to date has not been referred to in ''Doctor Who'', although Kate has referred to herself as a divorcee and "mother-of-two" in the programme.
* [[Tegan Jovanka]] is a former airhostess and former companion to the Fourth and [[Fifth Doctor|Fifth]] Doctors, she was hired to work as a freelancer for UNIT and employee by Kate Stewart before [[The Power of the Doctor]]. She met the [[Thirteenth Doctor|Thirteenth]] and assisted her by blowing up the Cybermen and the new UNIT base and saw a hologram of an aged Fifth Doctor.
*[[Ace (Doctor Who)|Ace]], who was a former companion to the [[Seventh Doctor|Seventh]], was a 16-year-old when she first met the Doctor. She was hired to work as a freelancer for UNIT and employed by Kate Stewart before "[[The Power of the Doctor]]". She met the [[Thirteenth Doctor|Thirteenth]] and assisted her by destroying the Daleks plan with her baseball bat and using her Nitro-9 with the assist of [[Graham O'Brien]] and saw a hologram of an aged Seventh Doctor.
* Shirley Anne Bingham is the 56th and current scientific adviser to UNIT who made her first appearance in [[The Star Beast (Doctor Who episode)|The Star Beast]] where she was in charge of investigating the seemingly crashed ship of [[List of Doctor Who villains|the Meep]]. She also assisted UNIT and the [[Fourteenth Doctor]] in investigating the eponymous Giggle in [[the Giggle]].
* [[Melanie Bush]], a computer programmer and former companion to the [[Sixth Doctor|Sixth]] and [[Seventh Doctor|Seventh]] Doctors, she was hired to work as a computer scientist for UNIT by Kate Stewart sometime after 2022's [[The Power of the Doctor]]. She was present for the [[Fourteenth Doctor|Fourteenth]] and [[Fifteenth Doctor|Fifteenth]] Doctors' battle against the Toymaker at UNIT Tower in 2023.
* Colonel Christofer Ibrahim is a UNIT field officer who answers directly to Kate Stewart and follows her without question. He made his debut in The Giggle, bringing the Doctor and Donna to his boss, and was present for the Toymaker's defeat. He later reappears in ''The Legend of Ruby Sunday'', ''Empire of Death'' and ''Lucky Day''; these episodes have a subplot where he is heavily implied to be in love with Kate.
* Morris Gibbons is a thirteen-year-old boy genius and scientific advisor who appears in the series 14 two-part finale "[[The Legend of Ruby Sunday]]" / "[[Empire of Death (Doctor Who episode)|Empire of Death]]".
* Ruby Sunday is revealed to have been recruited to UNIT after she and the Doctor parted ways. She is shown on Kate Stewart's personal staff alongside Shirley and Ibrahim, though her exact role has never been revealed. 

=== Other media ===
==== Originating in audio ====
* Colonel Vikram Shindi is a field officer in the ''UNIT: The New Series'' audio plays, an old-school, humourless soldier who follows Kate Stewart without question.
* Captain Josh Carter is a company officer in ''UNIT: The New Series'', more of a man of action.
* Lieutenant Sam Bishop is a company officer in ''UNIT: The New Series'', and serves as a troubleshooter.
* Lieutenant Jimmy Tan is a company officer introduced later in ''UNIT: The New Series''.

==== Originating in TV but expanded in other media ====
* Allison Williams is the assistant and scientific advisor to Professor Rachel Jensen when UNIT existed as the Incursion Countermeasures Group. She originated in ''Remembrance of the Daleks'' but was fleshed out in the ''Countermeasures'' audio series.