1973

May

 * 14 - the first American space station, Skylab, is launched. The Doctor claimed to have had involvement in its construction. (DW: Tooth and Claw)
 * Depending upon one's view of the UNIT dating controversy, it may have been the Third Doctor who participated in this.

December

 * 12 - Madeline Burton dies in Paris from a drug overdose, the Revolution Man cult (also known as 'The Second Coming of Ed Hill') collapsed without her influence. (EDA: ''Revolution Man)


 * Jo Grant plays Aladdin, Mike Yates plays Widow Twankey, and the Doctor plays the villain in the UNIT staff Christmas panto. (NA: No Future, Timewyrm: Revelation)

Unknown dates

 * A film version of "The Three Musketeers" is released. Genetic material from its principal stars, Michael York, Oliver Reed, Richard Chamberlain, and Frank Finlay, will be used to create Reprises of D'Artaganan, Athos, Aramis, and Porthos in Europa in the far future. (MA: Managra)


 * An archaeological expedition led by Aubrey Prior strips the tomb of Nephthys in Egypt. They tell the workers that it will be rebuilt in the British Museum. (MA: The Sands of Time)


 * In a possible alternate future or parallel timeline, various incarnations of The Doctor along with various companions, experience time-slipping between this year, 1993 and 2013 as the result of a ploy by The Rani. (DW: Dimensions in Time)

January

 * 06 - The Three Doctors Episode 2 First Broadcast


 * 13 - The Three Doctors Episode 3 First Broadcast


 * 19 - Max Adrian, who played King Priam in "The Myth Makers," dies in Wilford.


 * 20 - The Three Doctors Episode 4 First Broadcast. Final television appearance of William Hartnell. This episode ends the Doctor's exile on Earth and marks the beginning of the end of the UNIT era of the series, although UNIT would continue to play a role for several more seasons.


 * 27 - Carnival of Monsters Episode 1 First Broadcast

February

 * 03 - Carnival of Monsters Episode 2 First Broadcast


 * 10 - Carnival of Monsters Episode 3 First Broadcast


 * 17 - Carnival of Monsters Episode 4 First Broadcast


 * 24 - Frontier in Space Episode 1 First Broadcast

March

 * 03 - Frontier in Space Episode 2 First Broadcast


 * 10 - Frontier in Space Episode 3 First Broadcast


 * 17 - Frontier in Space Episode 4 First Broadcast


 * 24 - Frontier in Space Episode 5 First Broadcast


 * 31 - Frontier in Space Episode 6 First Broadcast. Final appearance of Roger Delgado as The Master, and final appearance of the Master until The Deadly Assassin.

April

 * 07 - Planet of the Daleks Episode 1 First Broadcast


 * 14 - Planet of the Daleks Episode 2 First Broadcast


 * 21 - Planet of the Daleks Episode 3 First Broadcast


 * 28 - Planet of the Daleks Episode 4 First Broadcast

May

 * 02 - Target Books, an imprint of W.H. Allen, reissues the 1960s novelisations Doctor Who in an Exciting Adventure with the Daleks by David Whitaker, Doctor Who and the Crusaders, also by Whitaker, and Doctor Who and the Zarbi by Bill Strutton. The Daleks novel is retitled Doctor Who and the Daleks and retains this title in all further editions. These books (all adapting First Doctor stories) were the first of 156 such novelisations the imprint would publish between up to 1994, covering all but a half-dozen televised stories, along with several radio and audio dramas. Target's later parent company, Virgin Publishing, would continue to publish original fiction set in the Doctor Who universe until the end of its Bernice Summerfield line ended its association with the franchise in 1999, but with BBC Books holding the licence to publish original Doctor Who fiction from 1997, the publication of original novels would continue uninterrupted into 2008 and beyond.


 * 05 - Planet of the Daleks Episode 5 First Broadcast


 * 12 - Planet of the Daleks Episode 6 First Broadcast


 * 19 - The Green Death Episode 1 First Broadcast


 * 26 - The Green Death Episode 2 First Broadcast

June

 * 02 - The Green Death Episode 3 First Broadcast


 * 09 - The Green Death Episode 4 First Broadcast


 * 16 - The Green Death Episode 5 First Broadcast


 * 18 - Roger Delgado is killed in an automobile accident outside Neveshir, Turkey. In later interviews (for Myth Makers and others), Jon Pertwee would cite Delgado's death as a contributing factor, along with the departure of Barry Letts as producer, in his decision to leave the series in 1974.


 * 23 - The Green Death Episode 6 First Broadcast. Katy Manning leaves the series after this episode.

July

 * 30 - Guy Middleton, who played Colonel Attwood in "The Highlanders," dies.

August

 * 05 - Paul Kasey, who has played numerous monsters in the revived series of Doctor Who, Torchwood and The Sarah Jane Adventures, is born in Chatham, Kent.
 * TV Action publishes its final issue, ending its Doctor Who comic strip.

September

 * 01 - After several years in another publication, the Doctor Who comic strip resumes in TV Comic.

November

 * 23 - Tenth anniversary of the first broadcast of Doctor Who.

December

 * 15 - The Time Warrior Episode 1 First Broadcast. The diamond-shaped series logo is introduced, along with an early version of the Bernard Lodge-designed "tunnel" opening sequence that would become closely associated with the Tom Baker era. Elisabeth Sladen makes her series debut as Sarah Jane Smith, and the Sontarans are unveiled. This serial will also reveal the name of the Doctor's planet, Gallifrey.


 * 22 - The Time Warrior Episode 2 First Broadcast


 * 29 - The Time Warrior Episode 3 First Broadcast

Unknown date

 * Peter Bathurst, who played Hensell in "The Power of the Daleks" and Chinn in "The Claws of Axos," dies.
 * The Wookey Hole cave system, near Wells, England, opens as a tourist attraction after more than a century of exploration. In 1975 the caves are used as the filming location for Revenge of the Cybermen.