1978 (releases)


 * 7 January - Underworld Part 1 was first broadcast.
 * 14 January - Underworld Part 2 was first broadcast.
 * 19 January - PROSE: Doctor Who and the Face of Evil was first published.
 * 21 January - Underworld Part 3 was first broadcast.
 * 21 - Writer Geoffrey Orme died.
 * 25 January - Actor Fred Ferris died.
 * 28 January - Underworld Part 4 was first broadcast.
 * The punk rock group The Art Attacks released the single "I Am a Dalek" on Albatross Records.
 * 4 February - The Invasion of Time Part 1 was first broadcast.
 * 11 February - The Invasion of Time Part 2 was first broadcast.
 * 16 February - Doctor Who Discovers: The Conquerors was first published.
 * 17 February - Actor Rory Kinnear was born.
 * 18 February - The Invasion of Time Part 3 was first broadcast.
 * 25 February - The Invasion of Time Part 4 was first broadcast.
 * 4 March - The Invasion of Time Part 5 was first broadcast.
 * 11 March - The Invasion of Time Part 6 was first broadcast, concluding Season 15. Louise Jameson left the series with this episode. This was also the final appearance of K9 Mark I until the K9 spinoff TV series of 2009.
 * 30 March - PROSE: Doctor Who and the Horror of Fang Rock was first published.
 * 31 March - Actor Daniel Mays was born.
 * 1 April - Actor JJ Feild was born.
 * 14 April - Actor Michelle Duncan was born.
 * 20 April - Doctor Who Discovers: Strange and Mysterious Creatures was first published. The Doctor Who Discovers series had 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.
 * 11 May - Actor Warren Brown was born.
 * 18 May - PROSE: Doctor Who and the Tomb of the Cybermen was first published.
 * 17 June - Actor James Corden was born.
 * 29 June - PROSE: Doctor Who and the Time Warrior was first published.
 * 1 July - Actor Kenneth Benda died.
 * 8 July - Actor Eve Myles was born.
 * 10 July - Actor Bryan Dick was born.
 * 14 July - Actor Jack Woolgar died.
 * 20 July - PROSE: Doctor Who - Death to the Daleks was first published.
 * 9 August - Actor Daniela Denby-Ashe was born.
 * 29 August - Tom Baker and Mary Tamm were interviewed on BBC Radio 2's Pete Murray's Open House.
 * The Doctor Who Annual 1979 was published.
 * Terry Nation's Dalek Annual 1979 was published. This was the final release of the series.
 * 2 September - The Ribos Operation Part 1 was first broadcast. Mary Tamm joined as new companion Romana. This was also the first appearance of K9 Mark II. This episode 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 September - The Ribos Operation Part 2 was first broadcast.
 * 16 September - The Ribos Operation Part 3 was first broadcast.
 * 23 September - The Ribos Operation Part 4 was first broadcast.
 * 30 September - The Pirate Planet Part 1 was first broadcast. This was the first Doctor Who episode to be written by Douglas Adams.
 * 5 October - Actor May Warden died.
 * 7 October - The Pirate Planet Part 2 was first broadcast.
 * 14 October - The Pirate Planet Part 3 was first broadcast.
 * 21 October - The Pirate Planet Part 4 was first broadcast.
 * 28 October - The Stones of Blood Part 1 was first broadcast, marking the start of the hundredth TV story.
 * 30 October - Writer Brian Hayles died.
 * 4 November - The Stones of Blood Part 2 was first broadcast.
 * 11 November - The Stones of Blood Part 3 was first broadcast.
 * 11 - Actor Vivienne Bennett died.
 * 16 November - PROSE: Doctor Who and the Android Invasion was first published.
 * 18 November -  The Stones of Blood Part 4 was first broadcast.
 * 22 November - Tom Baker, Mary Tamm and Carole Ann Ford appeared on the BBC's Nationwide to celebrate Doctor Who's fifteenth Anniversary.
 * 25 November - The Androids of Tara Part 1 was first broadcast.
 * 28 November - Actor André Morell died.
 * During a break in production of 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 tried 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 December - The Androids of Tara Part 2 was first broadcast.
 * 7 December - PROSE: Doctor Who and the Sontaran Experiment was first published.
 * 9 December - The Androids of Tara Part 3 was first broadcast.
 * 16 December - The Androids of Tara Part 4 was first broadcast.
 * 20 December - Writer Eddie Robson was born.
 * 23 December - The Power of Kroll Part 1 was first broadcast.
 * 30 December - 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 were PROSE: Doctor Who and the Day of the Daleks and PROSE: Doctor Who and the Giant Robot.
 * 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.