Doctor Who Unbound is a series of audio plays produced by Big Finish Productions. Free from the constraints of continuity, the Doctor Who Unbound audios present a series of "What if...?" scenarios, and cast new actors in the role of the Doctor.

In Exile, Arabella Weir plays a female incarnation of the Doctor.^{[1][2][3][4][5][6]} American alternative weekly Houston Press's Jef Rouner described her portrayal as "one of the most melancholy of all the Doctors."^[5] Other actors who played the Doctor included Geoffrey Bayldon, David Collings, Derek Jacobi, and David Warner.^[3][5]

Sympathy for the Devil features UNIT during the transfer of sovereignty over Hong Kong in 1997.^[7] David Warner played an alternate Third Doctor in the story, which also saw Nicholas Courtney play an alternate version of The Brigadier and Mark Gatiss play an alternate version of The Master. Warner and Courtney reprised their roles for the eighth story in the range, Masters of War. In 2016, Warner and Gatiss reprised their roles as the Doctor and the Master respectively for The New Adventures of Bernice Summerfield audio drama series: The Unbound Universe and its sequel Ruler of the Universe in 2017. After being pulled from the Unbound universe into the regular continuity of the Doctor Who universe, both characters have made ongoing appearances in various Big Finish ranges.

In February 2022, after a 14-year hiatus, Big Finish Productions announced the return of Unbound. Two boxsets, compromising of 3 stories in each, feature Colin Baker as an alternate Warrior Doctor known as "The Doctor of War" in a universe where the Fourth Doctor made the ultimate decision on Skaro, destroying the Daleks and showing how events may have unfolded after that fateful decision was made. These boxsets were announced to be released in April and September 2022 respectively.^[8]

On the 28th of September 2022, Big Finish re-released the original first 8 stories in a download boxset titled Doctor Who: Unbound: 1-8 Collected.^[9]

From 2017 to 2021, David Bradley reprised the role of First Doctor in Big Finish's The First Doctor Adventures range, having played the character in the 2017 Christmas special "Twice Upon A Time" and 2022 Centenary special "The Power of the Doctor" as well as 2013 docudrama "An Adventure in Space and Time" in which he played original First Doctor actor William Hartnell. The latter which he co-starred with Jemma Powell, Jamie Glover and Claudia Grant who played actors Jaqueline Hill, William Russell and Carole Ann Ford in the docudrama as well as playing the actors's original parts of Barbara Wright, Ian Chesterton and Susan Foreman.^[10] On the 11th of February 2022, it was announced that Stephen Noonan would instead takeover the role of the First Doctor with a portrayal closer to the characters original depiction.^[11][12] In April 2022, Executive Producer Nicholas Briggs expressed interest in producing further stories with Bradley.^[12] In Issue 167 of Big Finish's magazine Vortex, Briggs teased further stories featuring Bradley's portrayal, saying "We’ve some very exciting plans afoot for further stories with David Bradley — something quite out of the ordinary and rather delightful.^[13]"On the 17th of April, it was announced Bradley would continue to play a new alternate version of the First Doctor alongside Powell, Glover and Grant as alternate versions of their respective characters but now apart of the Unbound range instead, in a series titled The First Doctor Unbound. Producer David O’Mahony stated that the series would take "stylistic inspiration" from “The Peter Cushing feature films".^[14]

Den of Geek's Andrew Blair selected Doctor Who Unbound as one of the ten Doctor Who stories that would make great musicals.^[25] The Mary Sue's Alan Kistler said "fans enjoyed imagining these alternate Doctors" of David Warner and Arabella Weir.^[3] American alternative weekly newspaper Houston Press's Jef Rouner said the series "fielded a fantastic set of stories."^[5]

In 2016, BBC America's Anglophenia featured a fan-made version of the Doctor Who theme music for Unbound's alternate Second Doctor.^[26]