Examples of Sequel Episode in Doctor Who.
- "Mission to the Unknown", the Dalek Cutaway, led into "The Daleks' Master Plan", two serials later. The latter story also follows up "The Time Meddler" with the return of the Monk.
- "The Moonbase" is sequel to "The Tenth Planet" in that it's the second appearance of the Cybermen in practically the same plot. A deleted line mentioned the Cybermen's Tombs on Telos, which leads into their next appearance, "The Tomb of the Cybermen".
- "The Abominable Snowmen" set up a long chain of sequel stories that would establish important elements of the Whoniverse. First there was "The Web of Fear", which brought back the Great Intelligence and Professor Travers. Then there was "The Invasion", which saw Colonel Lethbridge-Stewart promoted to Brigadier and UNIT established, plus a Suspiciously Similar Substitute for Professor Travers and his daughter Ann. Then came "Spearhead from Space", which followed up on what happened to the Brigadier and UNIT since "The Invasion" and reunited him with the Doctor, who he initially doesn't recognize on account of his regeneration. Finally, "Terror of the Autons" featured the Master (in his debut appearance) stealing a meteorite that was left behind after the events of "Spearhead from Space" in order to reawaken the Autons and summon the Nestene Consciousness back to Earth, which set off a whole season full of successive clashes between the Doctor and the Master.
- "The Curse of Peladon" was followed up by "The Monster of Peladon", depicting the next generation of Peladon's monarchy attempting to wrestle another flareup in xenophobia and nationalism after the kingdom joined the Galactic Federation. The serial even reused the same sets.
- "The Sea Devils" is a sequel to "Doctor Who and the Silurians", in that it established the titular monsters as cousins. It additionally acts as a sequel to "The Dæmons", following up on the Master's arrest at the end of that serial and seeing him engineer the Sea Devils' invasion of humankind while behind bars. "Warriors of the Deep" was a sequel to both Silurian stories.
- "Planet of the Daleks" is a sequel to both "Frontier in Space", immediately following up on the cliffhanger ending of that story and the Daleks' plot to invade Earth and Draconia, and "The Daleks", seeing the Doctor work with a new generation of Thals long after his initial visit to Skaro, by which point his exploits from that story have become the stuff of legend. Of note is that "Frontier in Space" and "Planet of the Daleks" were originally intended to be billed as one twelve-part serial (which would've tied it with "The Daleks' Master Plan" for the position of longest story by episode count) before being Divided for Publication as two interconnected six-parters.
- All the Dalek stories from "Genesis of the Daleks" until "Remembrance of the Daleks" follow an ongoing story involving the Doctor's conflict with Davros, which set both the Dalek Civil War and the Last Great Time War in motion.
- "The Invasion of Time" follows up on "The Deadly Assassin", featuring the Doctor returning to Gallifrey again to claim the title of Lord President. In the earlier serial, he nominated himself for the position to weasel out of a sham trial, and the only other known candidate, Goth, was killed by the Master, making the Doctor the winner by default.
- Peter Davison's first year had a story called "Kinda", in which a plot point was a snake-like being called the Mara gaining influence over Tegan to further its goals. The next year saw the story "Snakedance", penned by the same writer, in which we learn that the Mara still has control over Tegan and possesses her once again in order to achieve physical form. There were plans for a third outing, but nothing came of fit.
- "Arc of Infinity" is a sequel to "The Three Doctors", in that it saw the return of Omega.
- "Attack of the Cybermen" is a sequel to three separate serials. In chronological order, it follows up on "The Tenth Planet" by featuring the Cybermen attempting to go back in time to prevent the destruction of Mondas during that serial, "The Tomb of the Cybermen" by being set in the titular tombs and elaborating upon how and why the Cybermen set up shop on Telos, and "Resurrection of the Daleks" by bringing back the mercenary Lytton.
- "Timelash" is a sequel to an untelevised adventure the Third Doctor had with Jo.
- "Time and the Rani" to "The Mark of the Rani".
- "Boom Town" continues the story of a Slitheen who survived the events of "Aliens of London"/"World War Three".
- "The End of the World", "New Earth" and "Gridlock" are season-apart stories loosely connected to the Face of Boe's final message to the Doctor.
- Satellite Five (and all the mess the Doctor's involvement caused) reappears in "Bad Wolf"/"The Parting of the Ways", after an assumed one-off encounter with the Mighty Jagrafess in "The Long Game".
- While Torchwood was a recurring Arc Word in series 2 (with the Doctor meeting a group identifying as the Torchwood Archive in "The Impossible Planet"/"The Satan Pit"), the Doctor's only direct encounters were at the founding in "Tooth and Claw" and his capture by (and the subsequent slaughtering of the team of by the real villains) Torchwood London in "Army of Ghosts"/"Doomsday".
- The Dalek episodes from "Army of Ghosts"/"Doomsday" to "Journey's End" directly follow on from one another. Depending on interpretation, the surviving Daleks from "Victory of the Daleks" may have come from the Dalek invasion of "The Stolen Earth". A similar use happens with Cybus Cyberman stories from "Rise of the Cybermen" to "The Next Doctor", which, subsequently, also involves the aforementioned "Army of Ghosts".
- The two televised spin-offs Torchwood and The Sarah Jane Adventures had episodes that follow on from Doctor Who stories as well:
- ''Cyberwoman'' revolved around Lisa Hallett, Ianto Jones' girlfriend who was partially converted by the Cybermen from the Battle of Canary Wharf (where they previously worked for Torchwood One) in "Army of Ghosts"/"Doomsday".
- "Utopia", the first episode of the 3-part finale for Series 3, was introduced from the ending of ''End of Days'', with Jack disappearing after hearing the sound of the TARDIS to join up with the Doctor and Martha when they materialise in Cardiff.
- ''Revenge of the Slitheen'' has the titular antagonists drain the energy of the sun, in their plan to destroy the world as revenge for their relative's deaths in Downing Street after the events of "Aliens of London"/"World War Three". Sarah Jane even mentions to herself "Slitheen in Downing Street" as something a "friend" (Rose Tyler) said to her once.
- Commander Kaagh, the main antagonist of ''The Last Sontaran'' is known to be the last surviving Sontaran from their failed invasion with the ATMOS devices and the destruction of their mothership from "The Sontaran Stratagem"/"The Poison Sky", blaming the destruction on the Doctor. Sarah Jane also mentioned meeting Sontarans twice.
- "The End of Time" picks up from the Master's death at the end of "Last of the Time Lords".
- Series 4, 5 and 6 have a recurring string of non-consecutive River Song episodes ("Silence in the Library"/"Forest of the Dead"; "The Time of Angels"/"Flesh and Stone", "The Pandorica Opens"/"The Big Bang"…) though from her point of view, they're prequel episodes.
- Series 5's "The Lodger", a Breather Episode just before the series 5 finale, was followed by series 6's "Closing Time", a Breather Episode just before the series 6 finale.
- The 50th anniversary special "The Day of the Doctor" has two sequel multi-part episodes in Series 9 (which aired two years later):
- "The Zygon Invasion"/"The Zygon Inversion" is a sequel to the B-plot, revealing what happened to the Zygons after the Doctor foiled their scheme.
- The finale three-parter "Face the Raven"/"Heaven Sent"/"Hell Bent" is a sequel to the A-plot as the Doctor returns to Gallifrey at last. "Face the Raven" itself doubles as a sequel to both Series 8's "Flatline", as Rigsy needs Clara and the Doctor's help once more, and "The Girl Who Died"/"The Woman Who Lived" from earlier in this season, as Ashildr/Me returns.
- The main plot of the third and final episode of the 60th anniversary trilogy, ''The Giggle'' features a long-awaited return of the Toymaker after 57 years from his original debut in ''The Celestial Toymaker''; awaiting a rematch from the Doctor for beating him in the Trilogic Games in his last encounter.
