1984

May

 * The Fifth Doctor defeated the Malus in Little Hodcombe. (DW: The Awakening)
 * 9 May - Turlough returned to Trion, Peri Brown joined the Fifth Doctor on his travels and Kamelion was destroyed. (DW: Planet of Fire, BFA: The Reaping)

Summer

 * Between 9 May and 28 September, Peri Brown's mother Janine and Howard Foster divorced. In spite of this, Janine kept her ex-husband's surname for the rest of her life. (BFA: The Reaping)

September

 * 28 September - The burial of Anthony Chambers was attended by Peri Brown and the Sixth Doctor. (BFA: The Reaping)

Unknown dates

 * H.C. Clements was bought by the Torchwood Institute. (DW: The Runaway Bride)
 * With the TARDIS caught inside a time corridor, the Fifth Doctor, Tegan and Turlough arrived in London, where they encountered canisters of Movellan virus and duplicates of humans created by the Daleks. They travelled across the corridor to meet the Daleks and their creator Davros in the future. After witnessing a huge amount of bloodshed in the early days of the Dalek Civil War, Tegan departed from the TARDIS in this year. Commander Lytton escaped from the future alive with his two police guards. (DW: Resurrection of the Daleks)
 * Lucie Miller's maternal aunt Patricia Ryder, whom she called "Auntie Pat," was killed by Zygons and replaced by her Zygon husband Trevor. (BFA: Grand Theft Cosmos)
 * Martha Jones was born. (IDW: The Forgotten)

January

 * 05 - DW: Warriors of the Deep Part 1 was first broadcast, launching Season 21 and marking the return of the Sea Devils and the Silurians, races not seen since the Jon Pertwee era.
 * 06 - DW: Warriors of the Deep Part 2 was first broadcast.
 * 12 - DW: Warriors of the Deep Part 3 was first broadcast.
 * DWN: Doctor Who - Mawdryn Undead was first published.
 * The final studio recording session for DW: The Caves of Androzani was held, concluding Peter Davison's time as the Fifth Doctor.
 * 13 - DW: Warriors of the Deep Part 4 was first broadcast.
 * 19 - DW: The Awakening Part 1 was first broadcast. This was the final two-part Doctor Who story produced as two twenty-five-minute episodes.
 * 20 - DW: The Awakening Part 2 was first broadcast.
 * 26 - DW: Frontios Part 1 was first broadcast.
 * 27 - DW: Frontios Part 2 was first broadcast.
 * Director Douglas Camfield died.

February

 * Doctor Who Monthly changed its title to Doctor Who Magazine.
 * 02 - DW: Frontios Part 3 was first broadcast.
 * 03 - DW: Frontios Part 4 was first broadcast.
 * 07 - Production commenced on DW: The Twin Dilemma, the first story of the Colin Baker era.
 * 08 - DW: Resurrection of the Daleks Part 1 was first broadcast. Due to a scheduling issue relating to the 1984 Winter Olympics, it was re-edited into two fifty-minute episodes rather than the usual four twenty-five-minute episodes. These were the first "double-length" episodes; the format was adopted permanently in the next season.
 * 15 - DW: Resurrection of the Daleks Part 2 was first broadcast. Janet Fielding left the series with this episode.
 * 23 - DW: Planet of Fire Part 1 was first broadcast. Nicola Bryant debuted as new companion Peri Brown.
 * 24 - DW: Planet of Fire Part 2 was first broadcast.

March

 * 01 - DW: Planet of Fire Part 3 was first broadcast.
 * 02 - DW: Planet of Fire Part 4 was first broadcast. Kamelion was destroyed and Mark Strickson left the series.
 * 08 - DW: The Caves of Androzani Part 1 was first broadcast.
 * 09 - DW: The Caves of Androzani Part 2 was first broadcast.
 * 15 - DW: The Caves of Androzani Part 3 was first broadcast.
 * DWN: Doctor Who - Kinda was first published. This was the last fully photographic Peter Davison cover.


 * 16 - DW: The Caves of Androzani Part 4 was first broadcast, ending in Peter Davison's regeneration into Colin Baker
 * 17 - John Dearth, who provided the voice of BOSS in DW: The Green Death and portrayed Lupton in DW: Planet of the Spiders, died.
 * 22 - DW: The Twin Dilemma Part 1 was first broadcast, launching the Colin Baker era. A slight modification was made to the series logo, adding a prism effect (which created the effect of it being curved); the logo used for merchandising, however, remained as per the version introduced in 1980. This was the first time since the switchover from William Hartnell to Patrick Troughton that a regeneration occurred before the end of a season, allowing the new Doctor to finish the year.
 * 23 - DW: The Twin Dilemma Part 2 was first broadcast.
 * 27 - Derek Francis, who played Nero in DW: The Romans, died from a heart attack in Wimbledon.
 * 29 - DW: The Twin Dilemma Part 3 was first broadcast.
 * 30 - DW: The Twin Dilemma Part 4 was first broadcast, concluding Season 21. This was the last half-hour episode until 1986 as Season 22 moved to a new format of forty-five-minute episodes. The 1984 season also marked the end of the show's twenty-four-episode long seasons. Beginning in 1985 the number of episodes was reduced to thirteen, later fourteen. A similar episode count persisted when the series returned in 2005.

April

 * 15 - Magician and comic Tommy Cooper, at one point a contender to play the Doctor, suffered a heart attack during a live TV performance and died backstage.
 * 22 - Michelle Ryan, who played Christina de Souza in DW: Planet of the Dead, was born.
 * 26 - Barry Gray, composer for Dr. Who films and Gerry Anderson projects, died.

May

 * 03 - DWN: Doctor Who - Snakedance was first published. With this release, Target Books returned to non-photographic covers, although for this and the next Fifth Doctor novelisation, a modified series logo incorporating a photograph of Peter Davison was utilised.
 * 15 - Tom Baker guest-starred in the American TV series, Remington Steele, in the part "Hounded Steele".
 * 24 - DWN: Doctor Who - Enlightenment was first published, a rare occasion when more than one novelisation was published at different times in a calendar month. It was the second and last use of the modified logo-and-photo branding for a Fifth Doctor novelisation and the final use of a photographic element on a Doctor Who fiction book until the 1988 novelisation of DWN: Time and the Rani. As Target was not allowed to feature artistic renderings of Peter Davison at the time, this was the last appearance of an image of the Fifth Doctor on a new novelisation, although Target was finally allowed to feature drawings of Davison when it issued new editions of many of its novelisations in the early 1990s. Target chose not to include images of the Sixth Doctor on initial releases of any of that era's novelisations; as a result, no image of a current Doctor appeared on the cover of a newly issued Target novelisation until DWN: Paradise Towers in December 1988.

June

 * 14 - BBC Broadcasting Research issued a Viewing Panel Report gauging response to Season 21 of Doctor Who, which had included the changeover from Fifth Doctor Peter Davison to Sixth Doctor Colin Baker. The season received an Appreciation Index of 57, while newcomer Baker received a "rather cool reception" from viewers.

July

 * 11 - Hugh Morton, who played Sir James Gregson in DW: The Seeds of Death, died.
 * 19 - DWN: Doctor Who - The Dominators was first published. It was the first non-Fifth Doctor novelisation in two years.

August

 * Doctor Who Annual 1985 was published.
 * 16 - DWN: Doctor Who - Warriors of the Deep was first published. It was the first fully-artistic Fifth Doctor novelisation cover and the first to use the new white-outline version of the Target Books logo.

September

 * 20 - DWN: Doctor Who - The Aztecs was first published. It was the last book to use the colour version of the Target Books logo.
 * REF: Doctor Who: The Key to Time was first published.

October

 * 10 - Joan Young, who played Catherine de Medici in DW: The Massacre of St Bartholomew's Eve, died.
 * Alan Lake (Herrick in DW: Underworld) committed suicide.
 * 18 - DWN: Doctor Who - Inferno was first published.
 * REF: The Doctor Who Pattern Book was first published.
 * Marvel Comics in the United States launched the monthly comic book Doctor Who. It carried colourised reprints of comic strips and other features from Doctor Who Magazine. Initially, Fourth Doctor material was featured. Fifth Doctor material followed the next year.

November

 * 7 - Hayden Jones, who provided the Auton voice in DW: Terror of the Autons, as well as playing Lenny Vosper in the following story, DW: The Mind of Evil, died.
 * 15 - DWN: Doctor Who - The Highlanders was first published.
 * REF: Doctor Who: Brain Teasers and Mind Benders was first published by Target Books, written by sixteen-year-old fan Adrian Heath.
 * 20 - Peter Welch, who played the Sergeant in DW: The Highlanders and Morgan in DW: The Android Invasion, died in Hammersmith, England.

December

 * 10 - DWN: Doctor Who - Frontios was first published.
 * 25 - Georgia Moffett, daughter of Peter Davison was born. After unsuccessfully trying out for the role of Rose Tyler, Moffett would play Jenny in DW: The Doctor's Daughter.

Unknown dates

 * Dennis Cleary, who took the part of a peasant in DW: The Reign of Terror, died.
 * Amara Karan, who would play Rita in DW: The God Complex, was born.

Trivia

 * This would be the last time Doctor Who would have a companion change mid-season until the 2012 Series 7 of the revived series - "Season 36".