1978

February
On 21 February, workers in Mexico City uncover the sacrificial stone at the base of the Great Temple. (NA: The Left-Handed Hummingbird)

December

 * At St. Benedict's School in Perivale, Chad Boyle almost hit Dorothy McShane with a brick, but was stopped by an adult Ace. (NA: Timewyrm: Revelation)
 * In an alternate timeline, Chad Boyle hit Dorothy McShane in the head with a brick, killing her. The Timewyrm recruited him in her battle against the Seventh Doctor and Ace. (NA: Timewyrm: Revelation) Although the novel dates this as 1976, this happens when Dorothy was eight years old (she was born in 1970).

Unknown dates

 * The Fourth Doctor and Romana searched for the third segment of the Key to Time on Earth, encountering the Ogri. (DW: The Stones of Blood)
 * Chris Parsons graduated from Cambridge and soon began his postgraduate studies at St Cedd's College. (DW: Shada)
 * The Doctor shipped the newly built K9 Mark III to Lavinia Smith's home in South Croydon as a gift for Sarah Jane Smith. However, the gift was not received by her until 18 December 1981. (KAC: A Girl's Best Friend)
 * The Eighth Doctor brought Anji Kapoor and Fritter to a Hollywood bar, where they met special effects photographer Ron von Arnim and later Noël Coward. Coward arrived here from the 1960s using pinking shears given to him by Iris Wildthyme, which could cut through the fabric of space and time. (EDA: Mad Dogs and Englishmen)

January

 * 2 - Debut of Blake's 7 on the BBC. Created by Terry Nation, the series had many connections to Doctor Who behind and in front of the camera.
 * 7 - DW: Underworld Part 1 was first broadcast.
 * 8 - Debut of All Creatures Great and Small on UK television. The series co-starred Peter Davison and launched him to stardom, leading to his being cast as the Fifth Doctor a few years later.
 * 14 - DW: Underworld Part 2 was first broadcast.
 * 19 - DWN: Doctor Who and the Face of Evil was first published.
 * 21 - DW: Underworld Part 3 was first broadcast.
 * 25 - Fred Ferris, who played Bert Rowse in DW: Planet of Giants, died.
 * 28 - DW: Underworld Part 4 was first broadcast.

February

 * The punk rock group The Art Attacks released the single "I Am a Dalek" on Albatross Records.
 * 4 - DW: The Invasion of Time Part 1 was first broadcast.
 * 11 - DW: The Invasion of Time Part 2 was first broadcast.
 * 16 - Doctor Who Discovers: The Conquerors was first published.
 * 18 - DW: The Invasion of Time Part 3 was first broadcast.
 * 25 - DW: The Invasion of Time Part 4 was first broadcast.

March

 * 4 - DW: The Invasion of Time Part 5 was first broadcast.
 * 11 - DW: The Invasion of Time Part 6 was first broadcast, concluding Season 15. Louise Jameson left the series with this episode. Also final appearance of K9 Mark I until the K9 spinoff TV series of 2009.
 * 30 - DWN: Doctor Who and the Horror of Fang Rock was first published.
 * 31 - Daniel Mays (Alex in DW: Night Terrors) was born.

April

 * 20 - Doctor Who Discovers: Strange and Mysterious Creatures was first published. The Doctor Who Discovers series has been planned to run as many as twenty-four volumes and at least three more books were in various stages of production. However, Target Books cancelled the series after this release, citing poor sales.

May

 * 18 - DWN: Doctor Who and the Tomb of the Cybermen was first published.

June

 * 29 - DWN: Doctor Who and the Time Warrior was first published.

July

 * 10 - Bryan Dick, who played Adam Smith in TW: Adam was born.
 * 14 - Jack Woolgar died.
 * 20 - DWN: Doctor Who - Death to the Daleks was first published.

August

 * 9 - Daniela Denby-Ashe (Mary in TW: Greeks Bearing Gifts) was born.
 * 29 - Tom Baker and Mary Tamm were interviewed on BBC Radio 2's Pete Murray's Open House.

September

 * Doctor Who Annual 1979 was published.
 * Terry Nation's Dalek Annual 1979 was published. This was the final release of the series.
 * 2 - DW: The Ribos Operation Part 1 was first broadcast. Mary Tamm joined as new companion Romana. Also first appearance of K9 Mark II. This launched Season 16 (although it was promoted as the show's fifteenth anniversary), and the series' first season-long story arc, The Key to Time.
 * 9 - DW: The Ribos Operation Part 2 was first broadcast.
 * 16 - DW: The Ribos Operation Part 3 was first broadcast.
 * 23 - DW: The Ribos Operation Part 4 was first broadcast.
 * 30 - DW: The Pirate Planet Part 1 was first broadcast. First Doctor Who episode to be written by Douglas Adams.

October

 * 5 - May Warden, who played the aged Sara Kingdom in DW: The Daleks' Master Plan, died.
 * 7 - DW: The Pirate Planet Part 2 was first broadcast.
 * 14 - DW: The Pirate Planet Part 3 was first broadcast.
 * 21 - DW: The Pirate Planet Part 4 was first broadcast.
 * 28 - DW: The Stones of Blood Part 1 was first broadcast, marking the start of the hundredth TV story.

November

 * 04 - DW: The Stones of Blood Part 2 was first broadcast.
 * 11 - DW: The Stones of Blood Part 3 was first broadcast.
 * Vivienne Bennett, who played Queen Elizabeth I in DW: The Chase, died in London.
 * 16 - DWN: Doctor Who and the Android Invasion was first published.
 * 18 - DW:  The Stones of Blood Part 4 was first broadcast.
 * 22 - Tom Baker, Mary Tamm and Carole Ann Ford appeared on the BBC's Nationwide to celebrate Doctor Who's fifteenth Anniversary.
 * 25 - DW: The Androids of Tara Part 1 was first broadcast.
 * 28 - André Morell, who played Marshal Gaspard de Saux-Tavannes in DW: The Massacre of St Bartholomew's Eve, died in London.

December

 * During a break in production of DW: The Armageddon Factor, Mary Tamm, Tom Baker and John Leeson performed 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 K9 tries to sing "We Wish You a Merry Christmas". Titled "Doug Who?", the skit circulated unofficially for years before being released in the Key to Time DVD set.
 * 2 - DW: The Androids of Tara Part 2 was first broadcast.
 * 7 - DWN: Doctor Who and the Sontaran Experiment was first published.
 * 09 - DW: The Androids of Tara Part 3 was first broadcast.
 * 16 - DW: The Androids of Tara Part 4 was first broadcast.
 * 23 - DW: The Power of Kroll Part 1 was first broadcast.
 * 30 - DW: The Power of Kroll Part 2 was first broadcast.

Unknown dates

 * American publisher Aeonian Press obtained 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 DWN: Doctor Who and the Day of the Daleks and DWN: Doctor Who and the Giant Robot.
 * Eve Myles, who played Gwen Cooper in Torchwood and Gwyneth in DW: The Unquiet Dead, was born in Ystradgynlais, Wales.
 * Tom Baker moonlighted from Doctor Who to appear in another BBC series, Late Night Story, which featured Baker performing dramatic readings of horror stories. At least five episodes, all between thirteen and fifteen minutes each, were recorded, but the series was never broadcast. Decades later, the five extant episodes were included as a bonus feature in the DVD box set of The Key to Time.