Summary

• Doctor Who has had numerous regenerations, but the best ones embody the show's themes of adventure and joy while introducing new directions.
• The worst regeneration is the Sixth Doctor's, as it's a cynical and emotionless removal of the actor from the role.
• The Twelfth Doctor's regeneration is the best, with a heartfelt speech that captures the essence of the character and provides a hopeful farewell.

Doctor Who debuted over fifty years ago, featuring over a dozen performers in the lead role of the Doctor thanks in part to the concept of regeneration. An ability possessed by their alien race known as the Time Lords, regeneration allows the Doctor to heal otherwise fatal injuries, changing their appearance and personality in the process. Introduced as a way to recast the role in-universe when the First Doctor William Hartnell's health deteriorated, each subsequent Doctor has departed the show with a regeneration.

While some of the regenerations feel like a cynical and blunt means of carrying the show forward with a new star, the most memorable ones have reinforced Doctor Who's overall themes of adventure and joy in the face of the universe's harsher elements. The best regenerations even count among the show's strongest sequences, highlighting the humanity of its very alien hero while introducing new Doctor Who actors and creative directions.

16 The Sixth Doctor (1987)

Time and the Rani

Colin Baker was ultimately fired from the role of the Doctor, and he refused to return just to be regenerated in season 24. In the subsequent story, Time and the Rani, the TARDIS is attacked by the Time Lord known as the Rani. The Doctor is mortally wounded and forced to regenerate while unconscious.

This regeneration is the worst because it's the most cynical application of the story device. It's a blunt event that removes a performer from the role without any genuine emotion or even an on-screen farewell. More than any other regeneration, the Sixth Doctor's is the weakest.

15 The Tenth Doctor (2008)

"Journey's End"

"Journey's End" starts with the Doctor regenerating after being shot by a Dalek in the previous episode. However, the cliffhanger is promptly undone when the Tenth Doctor simply heals himself with the regeneration energy and deposits the excess power into a copy of his hand (that creates a clone of him). The Tenth Doctor's fake-out regeneration remains the only time a Doctor fully ignored regenerating, making it one of the show's most infamous cop-outs. However, it does allow Rose Tyler and the Doctor's love story to achieve a conclusive ending thanks to the clone, giving it greater emotional heft.

14 The Seventh Doctor (1996)

Doctor Who: The Television Movie

After a nearly decade-long hiatus, Doctor Who returned in the form of a TV film. The Seventh Doctor, upon crashing into San Francisco in 1999, is shot by a gang. Taken to a hospital, his alien anatomy leads to the surgeons accidentally killing him mid-operation. While the regeneration is delayed by the circumstances (and subsequently fails to give Sylvester McCoy's Seventh Doctor a proper send-off), the frantic pacing and horror-tinted face morphing from the Seventh into the next incarnation of the character at least fits well into the infamously chaotic events of the TV film.

13 The Fourth Doctor (1981)

Logopolis

While preventing the Master's schemes, the Fourth Doctor is severely wounded by falling from a great height. His emotional final moments give way to the revelation that the mysterious Watcher following them is the next Doctor. The two fuse, regenerating into the Fifth Doctor.

For all his iconic additions to the character, Tom Baker's Fourth Doctor still has one of the franchise's weirdest regenerations. The wonky special effects, including a bizarre cocoon as the Doctor's body transforms, distract from the emotion of the scene. It's a strange ending to an otherwise solid departing story for the Fourth Doctor.

12 The Fifth Doctor (1984)

The Caves of Androzani

After being fatally poisoned alongside his assistant Peri, the Fifth Doctor uses the last antidote on his companion before succumbing to the toxin. The Fifth Doctor's regeneration is a far more internal affair, with his last moments spent reflecting on his fallen friends like Adric and enemies like the Master. The lead-up to his regeneration is more compelling than the event itself, however. His goodbye to Peri is emotionally wrenching, but the dated editing and effects of his internal conflict make his final scene more distracting than affecting.

11 The War Doctor (2013)

"The Day of the Doctor"

A major reveal of Doctor Who's fiftieth anniversary was the existence of a secret incarnation, who became a warrior during the Time War. John Hurt's War Doctor was an engaging contrast to the Tenth and Eleventh Doctors in that adventure, ultimately allowing himself to regenerate following their time together. The War Doctor's character growth across "The Day of the Doctor" gives his quick regeneration more emotional heft. Aware he'll lose his memories and become embittered at his perceived failings, he spends his final moments alone but content. It's a brief but sweet send-off for one of the shortest-lived Doctors.

10 The Eighth Doctor (2013)

"The Night of the Doctor"

In the prequel to "The Day of the Doctor," Paul McGann's Eighth Doctor largely avoids the Time War. Seriously wounded in a spaceship crash and horrified by the conflict, the Sisterhood of Karn allow him to dictate his regeneration—setting up the origins of the War Doctor. The emotional weight of the Doctor choosing to forgo his typical noble intentions lends this regeneration a lot of power. McGann fully sells the impact of this decision, broken by his need to become a Warrior instead of a Doctor. This gives his much-maligned Doctor a powerful and tragic farewell.

9 The First Doctor (1966/2017)

The Tenth Planet & "Twice Upon a Time"

The First Doctor succumbs to old age after his first encounter with the Cybermen, regenerating without warning. The regeneration itself is even harsher because the final episode of The Tenth Planet was lost in the BBC's archival wipes. Footage of the regeneration survived and was expanded upon in "Twice Upon a Time."

Without the more recent adventure, the First Doctor's regeneration is most memorable for its unprecedented nature. It's very sudden, a reminder of how alien the Doctor is. However, David Bradley's performance as the First Doctor gives it greater emotional heft, granting the First Doctor a fittingly bittersweet but hopeful ending.

8 The Second Doctor (1969)

The War Games

The oldest regeneration that survives fully intact, the Second Doctor regenerates after the other Time Lords of Gallifrey decide to punish him for his habit of interfering in the events of the universe. Despite his protests, the Second Doctor is the only version of the character to be forcibly regenerated without actually dying.

The Second Doctor's regeneration is a trippy affair. While the effects may be dated, they actually work in favor of the story by highlighting that other Time Lords can be effortlessly cruel and overwhelmingly powerful. The Second Doctor's regeneration adds to the lore of the franchise in a compelling way.

7 The Ninth Doctor (2005)

"The Parting of the Ways"

The first modern regeneration, the Ninth Doctor chooses to absorb the Time Vortex energy that would have otherwise killed Rose Tyler. The Ninth Doctor accepts this fate, spending his final moments comforting Rose and declaring that they were both truly fantastic before transforming into the Tenth Doctor. The Ninth Doctor's regeneration has served as a blueprint for each subsequent one. While quietly heartbreaking, the Doctor's refusal to bow to grief and instead focus on life highlights the bittersweet nature of regeneration. It's a tonal balancing act that future regenerations have further refined and improved upon.