1978

March

 * 8 - The first episode of a radio play by Douglas Adams entitled The Hitchhiker's Guide to the Galaxy airs on BBC Radio, launching an entertainment franchise that would in the coming decades include novels, sequel radio plays, a TV series and a movie. The Doctor was a fan of this series and referenced it on several occasions. (DW: Ghost Light and The Christmas Invasion)

Unknown dates

 * The Doctor and Romana search for the third segment of the Key to Time on Earth, encountering the Ogri. (DW: The Stones of Blood)
 * Chris Parsons graduates from Cambridge and soon begins his post-graduate studies at St. Cedd's College. (DW: Shada)
 * The Doctor ships the newly built K-9 Mark III to Lavinia Smith's home in South Croydon as a gift for Sarah Jane Smith. However, the gift is not received by her until 18 December 1981. (KAC: A Girl's Best Friend) it is unknown whether he does this before meeting Romana, or after, as he overides the randomiser many times in the next series, so he may have taken it to Sarah Jane then, or possibly after leaving Leela, as he may have dropped K9MKIII off while un packing K9MKII
 * The Doctor brings Anji Kapoor and Fritter to a Hollywood bar, where they meet special effects photographer Ron von Arnim and later Noël Coward, who has arrived here from the 1960s using pinking shears given him by Iris Wildthyme which could cut through the fabric of space and time. (EDA: Mad Dogs and Englishmen)

January

 * 7 - DW: Underworld Part One First Broadcast
 * 8 - Debut of All Creatures Great and Small on UK television. The series co-stars Peter Davison and launches him to stardom, leading to his being cast as the Fifth Doctor a few years later.
 * 14 - DW: Underworld Part Two First Broadcast
 * 19 - DWN: Doctor Who and the Face of Evil First Published.
 * 21 - DW: Underworld Part Three First Broadcast
 * 25 - Fred Ferris, who played the part of Bert Rowse in Planet of Giants, dies.
 * 28 - DW: Underworld Part Four First Broadcast

February

 * 4 - DW: The Invasion of Time Part One First Broadcast
 * 11 - DW: The Invasion of Time Part Two First Broadcast
 * 16 - Doctor Who Discovers: The Conquerors first published.
 * 18 - DW: The Invasion of Time Part Three First Broadcast
 * 25 - DW: The Invasion of Time Part Four First Broadcast

March

 * 4 - DW: The Invasion of Time Part Five First Broadcast
 * 11 - DW: The Invasion of Time Part Six First Broadcast. Louise Jameson leaves the series with this episode. Also final appearance of K-9 Mark I until the K-9 spinoff TV series of 2009.
 * 30 - DWN: Doctor Who and the Horror of Fang Rock First Published.

April

 * Doctor Who Discovers: Strange and Mysterious Creatures first published. Although the Doctor Who Discovers series has been planned to run as many as 24 volumes, and at least three more books are in various stages of production, Target Books cancels the series after this release, citing poor sales.

May

 * 18 - DWN: Doctor Who and the Tomb of the Cybermen First Published.

June

 * 29 - DWN: Doctor Who and the Time Warrior First Published.

July

 * 14 - Jack Woolgar dies.
 * 20 - DWN: Doctor Who - Death to the Daleks First Published.

September

 * Doctor Who Annual 1979 published.
 * Terry Nation's Dalek Annual 1979 published. Final release of the series.
 * 2 - DW: The Ribos Operation Part One First Broadcast. Mary Tamm joins as new companion Romana. Also first appearance of K-9 Mark II. This episode launches the series' first season-long story arc, The Key to Time.
 * 9 - DW: The Ribos Operation Part Two First Broadcast
 * 16 - DW: The Ribos Operation Part Three First Broadcast
 * 23 - DW: The Ribos Operation Part Four First Broadcast
 * 30 - DW: The Pirate Planet Part One First Broadcast

October

 * 5 - May Warden, who played the aged Sara Kingdom in DW: The Daleks' Master Plan, dies.
 * 7 - DW: The Pirate Planet Part Two First Broadcast
 * 14 - DW: The Pirate Planet Part Three First Broadcast
 * 21 - DW: The Pirate Planet Part Four First Broadcast
 * 28 - DW: The Stones of Blood Part One First Broadcast, marking the start of the 100th TV story.

November

 * 04 - DW: The Stones of Blood Part Two First Broadcast
 * 11 -
 * DW: The Stones of Blood Part Three First Broadcast
 * Vivienne Bennett, who played Queen Elizabeth I in "The Chase," dies in London.
 * 16 - DWN: Doctor Who and the Android Invasion First Published.
 * 18 -DW:  The Stones of Blood Part Four First Broadcast
 * 23 - Tom Baker, Mary Tamm and Carole Ann Ford appear on the BBC's "Nationwide" to celebrate Doctor Who's 15th Anniversary.
 * 25 - DW: The Androids of Tara Part One First Broadcast
 * 28 - André Morell, who played Marshal Gaspard de Saux-Tavannes in "The Massacre of St Bartholomew's Eve," dies in London.

December

 * During a break in production of The Armageddon Factor, Mary Tamm, Tom Baker and John Leeson perform a brief skit for the BBC staff Christmas video in which the Doctor and Romana flirt with each other over a bottle of whiskey and K-9 tries to sing "We Wish You a Merry Christmas". The skit circulates unofficially for years before being released in the Key to Time DVD set.
 * 2 - DW: The Androids of Tara Part Two First Broadcast
 * 7 - DWN: Doctor Who and the Sontaran Experiment First Published.
 * 09 - DW: The Androids of Tara Part Three First Broadcast
 * 16 - DW: The Androids of Tara Part Four First Broadcast
 * 23 - DW: The Power of Kroll Part One First Broadcast
 * 30 - DW: The Power of Kroll Part Two First Broadcast

Unknown dates

 * American publisher Aeonian Press obtains the US publication rights to some of the Target Books releases, issuing them in limited distribution hardcovers. Among the books reissued in this format are Doctor Who and the Day of the Daleks and Doctor Who and the Giant Robot.
 * Eve Myles, who plays Gwen Cooper in Torchwood and Gwyneth in Doctor Who is born in Ystradgynlais, Wales.
 * Tom Baker moonlights from Doctor Who to appear in another BBC series, Late Night Story, which featured Baker performing dramatic readings of horror stories. At least five episode, all between 13 and 15 minutes each, are recorded, but the series is never broadcast. Decades later, the five extant episodes are included as a bonus feature in the DVD box set of The Key to Time.