1968

1968 was an important year for the Time Lords. Cuthbert Simpson learned the randomiser code for the Doctor's TARDIS from Susan Seymour, (EDA: The Banquo Legacy) allowing the Time Lords to track the Eighth Doctor down. (EDA: The Ancestor Cell)

May

 * Jack Harkness was present for the Parisian student riots. (TWM: The Book of Jahi)

June

 * 21 - The cryogenically frozen World War I soldier Tommy Brockless was revived, as was the case on this date every year since 1919. Exploring the outside world, he was intrigued by the short skirts worn by young women. In 2008, he claimed that it was as if all of his Christmases had come at once. (TW: To the Last Man)

July

 * 18 - Lucia Moretti, a lover of Jack Harkness and the eventual mother of his daughter, began her work as a Torchwood agent. (TW: Children of Earth: Day Three)

October

 * The Olympics were held in Mexico City. (DW: The Underwater Menace )

December

 * 20 - Cristián Alverez met the Seventh Doctor in London. (NA: The Left-Handed Hummingbird)
 * 23 - The Sentience began stirring in Crook Marsham. (NA: Nightshade)
 * 24 - The Seventh Doctor and Ace arrived in Crook Marsham, and became involved in the fight against the Sentience. (NA: Nightshade)
 * 25 - The final battle against the Sentience took place. It departed Crook Marsham. Actor Edmund Trevithick died in the incident. (MA: Nightshade)

Unknown dates

 * The United Nations had by this time established protocols for first contact with alien life. (DW: The Sound of Drums)
 * The Monk deposited £200 in a London bank, planning to withdraw it with compound interest in two hundred years. (DW: The Time Meddler)

January

 * 06 - DW: The Enemy of the World Episode 3 was first broadcast.
 * 13 - DW: The Enemy of the World Episode 4 was first broadcast.
 * 20 - DW: The Enemy of the World Episode 5 was first broadcast.
 * 27 - DW: The Enemy of the World Episode 6 was first broadcast. The episode was followed by a specially shot scene of the Doctor addressing the viewers about the events of the next story.

February

 * 01 - Tom Baker makes his TV acting debut in an episode of Market in Honey Lane.
 * 03 - DW: The Web of Fear Episode 1 was first broadcast.
 * 10 - DW: The Web of Fear Episode 2 was first broadcast.
 * 17 - DW: The Web of Fear Episode 3 was first broadcast. First appearance of Nicholas Courtney as Col. (later Brigadier) Alistair Gordon Lethbridge-Stewart, a character that will become a consistent part of the Doctor Who universe for the next 40 years.
 * 24 - DW: The Web of Fear Episode 4 was first broadcast.

March

 * 02 - DW: The Web of Fear Episode 5 was first broadcast.
 * 09 - DW: The Web of Fear Episode 6 was first broadcast.
 * 16 - DW: Fury from the Deep Episode 1 was first broadcast.
 * 23 - DW: Fury from the Deep Episode 2 was first broadcast.
 * 30 - DW: Fury from the Deep Episode 3 was first broadcast.

April

 * 04 - Martin Luther King, Jr. was assassinated.
 * 06 - DW: Fury from the Deep Episode 4 was first broadcast.
 * Keith Pyott, who played Autloc in DW: The Aztecs died.
 * 13 - DW: Fury from the Deep Episode 5 was first broadcast.
 * 20 - DW: Fury from the Deep Episode 6 was first broadcast. Deborah Watling leaves the series with this episode.
 * 27 - DW: The Wheel in Space Episode 1 was first broadcast.

May

 * 04 - DW: The Wheel in Space Episode 2 was first broadcast. Debut of Wendy Padbury as new companion Zoe Heriot.
 * 11 - DW: The Wheel in Space Episode 3 was first broadcast.
 * 12 - Catherine Tate (Donna Noble) was born.
 * 18 - DW: The Wheel in Space Episode 4 was first broadcast.
 * 25 - DW: The Wheel in Space Episode 5 was first broadcast.
 * 28 - Kylie Minogue (Astrid Peth in DW: Voyage of the Damned) was born.

June

 * 01 - DW: The Wheel in Space Episode 6 was first broadcast, concluding the fifth season of Doctor Who. The episode ends with the Doctor proceeding to show Zoe a recording of a recent adventure, leading into a rebroadcast of DW: The Evil of the Daleks which will fill the gap before the start of the next season.
 * 06 - Robert Kennedy was assassinated.

August

 * 5 - Matt Jones, best known in the Doctor Who world for writing the Doctor Who episodes DW: The Impossible Planet/The Satan Pit and the Torchwood episode TW: Dead Man Walking, was born.
 * 10 - DW: The Dominators Episode 1 was first broadcast, launching Season 6.
 * 17 - DW: The Dominators Episode 2 was first broadcast.
 * 24 - DW: The Dominators Episode 3 was first broadcast.
 * 31 - DW: The Dominators Episode 4 was first broadcast.

September

 * Publication of the fourth Doctor Who Annual.
 * 07 - DW: The Dominators Episode 5 was first broadcast.
 * 14 - DW: The Mind Robber Episode 1 was first broadcast.
 * 21 - DW: The Mind Robber Episode 2 was first broadcast.
 * 28 - DW: The Mind Robber Episode 3 was first broadcast.

October

 * Frazer Hines releases the pop single "Who's Dr. Who?" on Major Minor Records.
 * 05 - DW: The Mind Robber Episode 4 was first broadcast.
 * 12 - DW: The Mind Robber Episode 5 was first broadcast, followed by several weeks of preemptions caused by coverage of the 1968 Summer Olympic Games in Mexico City.

November

 * 02 - DW: The Invasion Episode 1 was first broadcast. Terrance Dicks' long association with the Doctor Who franchise begins with this episode, on which he serves as script editor. Although the character was not yet identified by name, John Levene makes his debut as John Benton.
 * 09 - DW: The Invasion Episode 2 was first broadcast, in which UNIT was officially introduced. Alistair Gordon Lethbridge-Stewart appears as a brigadier for the first time, though he won't become a regular until 1970.
 * 16 - DW: The Invasion Episode 3 was first broadcast.
 * 23 - DW: The Invasion Episode 4 was first broadcast; this was also the show's 5th anniversary.
 * 30 - DW: The Invasion Episode 5 was first broadcast.

December

 * 07 - DW: The Invasion Episode 6 was first broadcast.
 * 14 - DW: The Invasion Episode 7 was first broadcast.
 * 21 - DW: The Invasion Episode 8 was first broadcast. Except for minor references, this was the last appearance of the Cybermen until DW: Revenge of the Cybermen in 1975.
 * 28 - DW: The Krotons Episode 1 was first broadcast. First Doctor Who script for the prolific Robert Holmes.