1983

August

 * 19 - Ianto Jones is born, probably in Cardiff. (TW: Fragments)

December

 * 10 - The Doctor, Benny, Roz, and Chris arrive in Little Caldwell, England. Benny is reunited with her father. (NA: Return of the Living Dad)

Undated

 * The Brigadier, now retired and working at Brendon Public School, meets the Doctor and in the ensuing adventure meets his younger self from 1977, causing his younger self to lose all memory of the Doctor and experience a breakdown, while his 1983 self regains his memory. Turlough joins the Doctor on his travels, although unknown to the Doctor, he does so under the orders of the Black Guardian. (DW: Mawdryn Undead)


 * According to the Brigadier, Harry Sullivan is doing "hush-hush" work on behalf of NATO at this time. (DW: Mawdryn Undead)


 * After the Fifth Doctor departs, the Brigadier reactivates his relationship with UNIT (as suggested by DW: The Five Doctors) eventually returning to active duty (at some point before DW: Battlefield).


 * The Doctor and the Brigadier are abducted by Borusa while attending a UNIT reunion. (DW: The Five Doctors)


 * Jason Kane is born, in the suburbs of London. (NA: Return of the Living Dad)


 * Ace burns down Gabriel Chase. (DW: Ghost Light)

January

 * 03 - DW: Arc of Infinity Episode 1 is first broadcast, launching Doctor Who's 20th season. Future Sixth Doctor Colin Baker makes his first appearance on the series, but as a different character.
 * 05 - DW: Arc of Infinity Episode 2 is first broadcast.
 * 11 - DW: Arc of Infinity Episode 3 is first broadcast.
 * 12 - DW: Arc of Infinity Episode 4 is first broadcast.
 * 18 - DW: Snakedance Episode 1 is first broadcast.
 * 19 - DW: Snakedance Episode 2 is first broadcast.
 * 25 - DW: Snakedance Episode 3 is first broadcast.
 * 26 - DW: Snakedance Episode 4 is first broadcast.

February

 * 01 - DW: Mawdryn Undead Episode 1 is first broadcast. Mark Strickson joins as new companion Vislor Turlough, while Nicholas Courtney makes his first appearance as Alistair Gordon Lethbridge-Stewart since Terror of the Zygons. This serial is the first to definitively establish that the current incarnation of the Doctor is the fifth.
 * 02 - DW: Mawdryn Undead Episode 2 is first broadcast.
 * 08 - DW: Mawdryn Undead Episode 3 is first broadcast.
 * 09 - DW: Mawdryn Undead Episode 4 is first broadcast.
 * 15 - DW: Terminus Episode 1 is first broadcast.
 * 16 - DW: Terminus Episode 2 is first broadcast.
 * 20 - Peter Glaze, who played the City Administrator in DW: The Sensorites and the Brigadier in a Doctor Who parody segment of Crackerjack!, dies in Dartford, England.
 * 22 - DW: Terminus Episode 3 is first broadcast.
 * 23 - DW: Terminus Episode 4 is first broadcast. Sarah Sutton leaves the series with this episode.

March

 * Filming and studio recording for DW: The Five Doctors occurs this month.
 * REF: The Doctor Who Technical Manual is first published.
 * 01 - DW: Enlightenment Episode 1 is first broadcast.
 * 02 - DW: Enlightenment Episode 2 is first broadcast.
 * 08 - DW: Enlightenment Episode 3 is first broadcast.
 * 09 - DW: Enlightenment Episode 4 is first broadcast.
 * 15 - DW: The King's Demons Episode 1 is first broadcast. Introduction of the android companion Kamelion.
 * 16 - DW: The King's Demons Episode 2 is first broadcast, technically concluding Season 20, although the later special DW: The Five Doctors will also be considered part of Season 20.
 * 21 - Bruno Langley, who portrayed companion Adam Mitchell in 2005, is born in Devon, England.

April

 * 15 - DWN: Doctor Who - Time-Flight is first published.

May

 * 02 - 10th anniversary of the launch of Target Books' line of Doctor Who novelisations.
 * 05 - DWN: Doctor Who - Meglos is first published. This was the final televised Fourth Doctor story to be novelised. Due to licensing issues, no novelisations were ever officially published for DW: The Pirate Planet, DW: City of Death or the unfinished/unbroadcast DW: Shada. Target Books would publish one more Fourth Doctor novelisation, DWN: The Pescatons, based upon an audio drama, in 1991.

June

 * 16 - DWN: Doctor Who - Castrovalva is first published.
 * 23 - Publication of Doctor Who: Daleks Omnibus, a hardcover Target Books collection reprinting the Terrance Dicks novelisations DWN: Doctor Who and the Dalek Invasion of Earth, DWN: Doctor Who and the Day of the Daleks and DWN: Doctor Who and the Planet of the Daleks.

July

 * 21 - DWN: Doctor Who - Four to Doomsday is first published.

August

 * The BBC announces that Colin Baker - no relation to Tom Baker - has been cast as the Sixth Doctor.
 * Doctor Who Annual 1984 published.
 * 18 - DWN: Doctor Who - Earthshock is first published.

September

 * 13 - REF: Doctor Who: A Celebration first published.
 * 15 - DWN: Doctor Who - Terminus is first published.

October

 * REF: Doctor Who: The Making of a Television Series published in paperback.
 * 14-19 Filming for DW: Planet of Fire takes place in Lanzarote, Canary Islands, marking the first time Doctor Who has been filmed outside the European continent.
 * 20 - DWN: Doctor Who - Arc of Infinity is first published.

November

 * REF: Doctor Who: The Unfolding Text, one of the first widely published scholarly works on the franchise, first published in both the UK and US.
 * 19 - For the first time in nearly 10 years, Doctor Who makes the cover of the Radio Times. It'll be another decade before this happens again, making this the last Radio Times cover to be published during the original series' run.
 * 23 - 20th anniversary of the first broadcast of Doctor Who.
 * DW: The Five Doctors is broadcast for the first time. However, PBS affiliates in the United States (which are also received on cable television in Canada) it before the BBC, the first time America has seen a Doctor Who story before the UK. This version is slightly truncated compared to the version shown two days later in the UK. This is the first "feature-length" regular episode of Doctor Who produced. The special features the return of Patrick Troughton and Jon Pertwee (with Tom Baker represented by footage from the unbroadcast DW: Shada). Richard Hurndall makes his first and only appearance as the First Doctor. Numerous companions from all eras of the series appear. Although broadcast closer to the start of Season 21, it is considered part of the anniversary Season 20 and, thus, its belated finale.
 * 24 - DWN: Doctor Who - The Five Doctors is first published. This is the first time a Target Books novelisation has been published before the UK broadcast premiere of an episode. According to the 2008 DVD release of DW: The Five Doctors, this is widely believed to have been an error.
 * 25 - DW: The Five Doctors is first broadcast in the UK, as part of that year's Children in Need fund-raising drive.

Unknown date

 * Magnet Books, a subsidiary of Methuen Children's Books, publishes Doctor Who Quiz Book of Science, Doctor Who Quiz Book of Space and Doctor Who Quiz Book of Magic, all by Michael Holt, the remainder of the Doctor Who Quiz Book line. These illustrated paperback books (published in the same format as Target Books novelisations) contain original short stories featuring the Fifth Doctor, Nyssa and Tegan Jovanka that set up short quizzes related to the subject matter of the book. The first book in the series had been published in 1982.