1978 (releases)


 * 7 January - Underworld Part One debuted on BBC1.
 * 14 January - Underworld Part Two debuted on BBC1.
 * 19 January - PROSE: Doctor Who and the Face of Evil was first published.
 * 21 January - Underworld Part Three debuted on BBC1.
 * 28 January - Underworld Part Four debuted on BBC1.
 * The punk rock group The Art Attacks released the single "I Am a Dalek" on Albatross Records.
 * 4 February - The Invasion of Time Part One debuted on BBC1.
 * 11 February - The Invasion of Time Part Two debuted on BBC1.
 * 16 February - Doctor Who Discovers: The Conquerors was first published.
 * 18 February - The Invasion of Time Part Three debuted on BBC1.
 * 25 February - The Invasion of Time Part Four debuted on BBC1.
 * 4 March - The Invasion of Time Part Five debuted on BBC1.
 * 11 March - The Invasion of Time Part Six debuted on BBC1, 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.
 * 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.
 * 18 May - PROSE: Doctor Who and the Tomb of the Cybermen was first published.
 * 29 June - PROSE: Doctor Who and the Time Warrior was first published.
 * 20 July - PROSE: Doctor Who - Death to the Daleks was first published.
 * 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 One debuted on BBC1. 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 Two debuted on BBC1.
 * 16 September - The Ribos Operation Part Three debuted on BBC1.
 * 23 September - The Ribos Operation Part Four debuted on BBC1.
 * 30 September - The Pirate Planet Part One debuted on BBC1. This was the first Doctor Who episode to be written by Douglas Adams.
 * 7 October - The Pirate Planet Part Two debuted on BBC1.
 * 14 October - The Pirate Planet Part Three debuted on BBC1.
 * 21 October - The Pirate Planet Part Four debuted on BBC1.
 * 28 October - The Stones of Blood Part One debuted on BBC1, marking the start of the hundredth TV story.
 * 4 November - The Stones of Blood Part Two debuted on BBC1.
 * 11 November - The Stones of Blood Part Three debuted on BBC1.
 * 16 November - Doctor Who and the Android Invasion was first published.
 * 18 November -  The Stones of Blood Part Four debuted on BBC1.
 * 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 One debuted on BBC1.
 * 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 Two debuted on BBC1.
 * 7 December - Doctor Who and the Sontaran Experiment was first published.
 * 9 December - The Androids of Tara Part Three debuted on BBC1.
 * 16 December - The Androids of Tara Part Four debuted on BBC1.
 * 23 December - The Power of Kroll Part One debuted on BBC1.
 * 30 December - The Power of Kroll Part Two debuted on BBC1.