1973

May

 * 14 - The first American space station, Skylab, was launched. The Tenth Doctor claimed to have been involved in its construction. (TV: Tooth and Claw)

November

 * Barbara Chesterton took her son John to the British Museum to look at the Roman exhibit. (PROSE: Byzantium!)

December

 * 12 - Madeline Burton died in Paris from a drug overdose. The Revolution Man cult (also known as 'The Second Coming of Ed Hill') collapsed without her influence. (PROSE: Revolution Man)
 * Jo Grant played Aladdin, Mike Yates played Widow Twankey and the Third Doctor played the villain in the UNIT staff Christmas panto. (PROSE: No Future, Timewyrm: Revelation)

Unknown dates

 * A film version of The Three Musketeers was released. Genetic material from its principal stars, Michael York, Oliver Reed, Richard Chamberlain and Frank Finlay were used to create Reprises of D'Artagnan, Athos, Aramis and Porthos in Europa in the far future. (PROSE: Managra)
 * An archaeological expedition led by Aubrey Prior stripped the tomb of Nephthys in Egypt. They told the workers it would be rebuilt in the British Museum. (PROSE: The Sands of Time)
 * Kathleen Dudman, Ace's maternal grandmother, died. Although she was only three years old at the time, Ace distinctly remembered that her mother Audrey cried for days afterwards. (AUDIO: Night Thoughts)
 * Noël Coward died. He knew in advance that he would die during this year due to his status as a time traveller. (PROSE: Mad Dogs and Englishmen)

January

 * 06 - TV: The Three Doctors Episode Two was first broadcast.
 * 8 - Actor Dudley Foster died.
 * 13 - TV: The Three Doctors Episode Three was first broadcast.
 * 19 - Actor Max Adrian died in.
 * 20 - TV: The Three Doctors Episode Four was first broadcast. This was the final television appearance of William Hartnell. This episode ended the Third Doctor's exile on Earth and marked the beginning of the end of the UNIT era of the series, although UNIT continued to play a role for several more seasons.
 * 27 - TV: Carnival of Monsters Episode One was first broadcast. Ian Marter, later to play companion Harry Sullivan and also write several acclaimed novelisations for Target Books, made his first appearance on Doctor Who.
 * 29 - Actor Henry Gilbert died.

February

 * 03 - TV: Carnival of Monsters Episode Two was first broadcast.
 * 10 - TV: Carnival of Monsters Episode Three was first broadcast.
 * 17 - TV: Carnival of Monsters Episode Four was first broadcast.
 * 24 - TV: Frontier in Space Episode One was first broadcast.

March

 * 03 - TV: Frontier in Space Episode Two was first broadcast.
 * 10 - TV: Frontier in Space Episode Three was first broadcast.
 * 17 - TV: Frontier in Space Episode Four was first broadcast.
 * 24 - TV: Frontier in Space Episode Five was first broadcast.
 * 31 - TV: Frontier in Space Episode Six was first broadcast. This was the final appearance of Roger Delgado as the Master and the final appearance of the Master until TV: The Deadly Assassin.

April

 * 07 - TV: Planet of the Daleks Episode One was first broadcast.
 * 14 - TV: Planet of the Daleks Episode Two was first broadcast.
 * 21 - TV: Planet of the Daleks Episode Three was first broadcast and Katsuyuki Konishi who dubbed the Ninth Doctor in Japan was born.
 * 28 - TV: Planet of the Daleks Episode Four was first broadcast.

May

 * 02 - Target Books, an imprint of W.H. Allen, reissued the 1960s novelisations PROSE: Doctor Who in an Exciting Adventure with the Daleks by David Whitaker, PROSE: Doctor Who and the Crusaders, also by Whitaker and PROSE: Doctor Who and the Zarbi by Bill Strutton. The Daleks novel was retitled Doctor Who and the Daleks and retained this title in all further editions. These books (all adapting First Doctor stories) were the first of one hundred fifty-six such novelisations the imprint published 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, continued to publish original fiction set in the Doctor Who universe until the conclusion of its Bernice Summerfield line ended its association with the franchise in 1999. With BBC Books holding the licence to publish original Doctor Who fiction from 1997, the publication of original novels continued uninterrupted into 2011 and beyond.
 * 05 - TV: Planet of the Daleks Episode Five was first broadcast.
 * 12 - TV: Planet of the Daleks Episode Six was first broadcast.
 * 19 - TV: The Green Death Episode One was first broadcast.
 * 26 - TV: The Green Death Episode Two was first broadcast.

June

 * 01 - Actor Adam Garcia was born in Wahroonga, New South Wales, Australia.
 * 01 - Actor Rene Zagger was born.
 * 02 - TV: The Green Death Episode Three was first broadcast.
 * 09 - TV: The Green Death Episode Four was first broadcast.
 * 16 - TV: The Green Death Episode Five was first broadcast.
 * 18 - Roger Delgado was killed in an car accident outside Neveshir, Turkey whilst being driven to the film location for the subsequently-cancelled Bell of Tibet. In later interviews (for Myth Makers and others), Jon Pertwee cited 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 - TV: The Green Death Episode Six was first broadcast, ending the tenth season. Katy Manning left the series after this episode. This was the final use of the series logo introduced in 1970 until the 1996 TV movie, in which a similar, though not identical, logo would be used, and the last to use the word "Episode" to designate the sections of the story; henceforth they were titled as "Part".

July

 * 30 - Actor Guy Middleton died.
 * 31 - Actor Daniel Evans was born.

August

 * 05 - Actor Paul Kasey was born in Chatham, Kent.
 * TV Action published its final issue, ending its Doctor Who comic strip.

September

 * 01 - After several years in another publication, the Doctor Who comic strip resumed in TV Comic.
 * The Doctor Who Annual 1974 was published.
 * 11 - Actor Rollo Gamble died.

November

 * 23 - This was the tenth anniversary of the first broadcast of Doctor Who.

December

 * 03 - Sylvester McCoy made one of his first TV appearances playing a robot in an episode of Roberts Robots.
 * 15 - TV: The Time Warrior Part One was first broadcast, launching Season 11. A diamond-shaped series logo was introduced - it became one of the franchise's most recognisable branding - along with an early version of the Bernard Lodge-designed "tunnel" opening sequence that became closely associated with the Tom Baker era. Elisabeth Sladen made her series debut as Sarah Jane Smith, and the Sontarans were unveiled. This story also revealed the name of the Doctor's planet: Gallifrey.
 * 15 - Doctor Who was featured on the cover of the Radio Times. This was the last time the series would be so featured for the next ten years.
 * 22 - TV: The Time Warrior Part Two was first broadcast.
 * 29 - TV: The Time Warrior Part Three was first broadcast.

Unknown dates

 * The Wookey Hole caves system, near Wells, England, opened as a tourist attraction after more than a century of exploration. In 1975 the caves were used as the filming location for TV: Revenge of the Cybermen.