Director: Sam Raimi
Dr. Stephen Strange (Benedict Cumberbatch) casts a forbidden spell that opens the door to the multiverse, including an alternate version of himself, whose threat to humanity is too great for the combined forces of Strange, Wong (Benedict Wong), and Wanda Maximoff (Elizabeth Olsen).
- Benedict Cumberbatch [Sinister Strange/Defender Strange/Supreme Strange]
- John Krasinski [Reed Richards/Mister Fantastic]
- Ross Marquand [Ultron Sentries] (voice)
- Anson Mount [Blackagar Boltagon/Black Bolt]
- Patrick Stewart [Charles Xavier/Professor X]
- Michael Stuhlbarg [Dr. Nicodemus West] (off-screen; revived)
- Topo Wresniwiro [Master Hamir]
- Hayley Atwell [Peggy Carter/Captain Carter]
- Sheila Atim [Sara]
- Ruth Livier [Elena Chavez] (possibly)
- Chess Lopez [Amalia Chavez] (possibly)
- Lashana Lynch [Maria Rambeau/Captain Marvel]
- Yenifer Molina [Gargantos] (voice)
- Elizabeth Olsen [Wanda Maximoff/Scarlet Witch] (possibly)
- Sam Raimi initially didn't want to direct any future superhero films, having lost faith in himself due to the critical and audience backlash he received from Spider-Man 3 (2007) due to studio interference from Sony. However, getting the call from his agent about this film encouraged him to try again, as he had thoroughly enjoyed the first Doctor Strange film (as well as the character himself) and wanted see if he could live up to the challenge of meeting the audience's expectations once again.
- Elizabeth Olsen flew to London to work on this film just two days after she finished filming WandaVision (2021).
- Director Sam Raimi previously added two references to the character Doctor Strange in Spider-Man 2 (2004): -Joe's Pizza (where Peter Parker is working at the beginning) and the billboard showing Mary Jane are located on Bleecker Street (where Doctor Strange's Sanctum Santorum is located). -The name of Doctor Strange is suggested to J. Jonah Jameson as a possible name for Dr. Octavius, to which Jameson replies: "But it's taken!"
- Benedict Cumberbatch revealed in an interview that Benedict Wong broke about four ribs when he slammed into something during a stunt.
- One poster displays Hinduism motifs, namely the many selves and many arms the Sorcerers take on. In Hindu Mythology, having many avatars is a sign of ultimate power. Wanda in the same poster takes on the role of Kali, the goddess of death but not an evil goddess, as she is also the goddess of motherhood.
- Sam Raimi's first directed feature film in 9 years since Oz the Great and Powerful (2013).
- Sam Raimi has observed that due to the chaotic production process he and the screenwriters essentially figured out the movie during filming, with the ending being conceptualized about halfway through the shoot.
- The one-eyed tentacle monster in the film is known in the Marvel comics as Shuma-Gorath, who was named from a phrase in the Robert E. Howard short story "The Curse of the Golden Skull", published in Spring 1967. Due to rights issues between Marvel and Howard's estate, the film has the monster renamed Gargantos, after a sea monster in the Marvel comics. The creature was already briefly introduced in the Marvel Universe, in the episode What If...?: What If... Captain Carter Were the First Avenger? (2021).
- Elizabeth Olsen was largely unaware of the Multiverse of Madness story while filming WandaVision (2021) and tried to ensure Maximoff's role in the film honored the events of the series rather than having the series be affected by the film.
- The music spell fight between Strange and Sinister Strange was originally written like a normal magic fight in the script but it was conceived by storyboard artist Doug Lefler after seeing a concept art of Sinister Strange's abode in the fallen dimension with a piano in the middle of it.
- While most MCU films are released under the genres of Action, Comedy, Drama, Sci-Fi, and Fantasy, this will be the first film in the MCU to be released under the Horror genre.
- This movie was originally meant to be before Spider-Man: No Way Home (2021) before the COVID-19 Pandemic forced the schedules to be altered and for this movie to ultimately come after it.
- The first Marvel movie to be specifically credited as "a Kevin Feige production."
- This is the fifth MCU film in a row after Black Widow (2021), Shang-Chi and the Legend of the Ten Rings (2021), Eternals (2021) and Spider-Man: No Way Home (2021) to be denied a release in China.
- The film is tied into and takes place after WandaVision (2021) and Spider-Man: No Way Home (2021).
- One poster displays statues of a tiger with wings and a female goddess. These are known as Hoggoth and Oshtur, who in the Marvel Comics, along with Agamotto, form the trinity of gods of magic known as the Vishanti.
- According to director Sam Raimi, almost 40 minutes of additional scenes were cut from the film during post-production.
- This is composer Danny Elfman's second MCU film, after Avengers: Age of Ultron (2015).
- Scott Derrickson, director of the previous film Doctor Strange (2016), was set to return. However, due to creative differences with Marvel, he stepped down. He stays as the film's executive producer.
- Benedict Cumberbatch grew out Doctor Strange's goatee for real in this film, rather than merely putting on a fake one as seen in his previous appearances.
- Gomez wanted to remain faithful to the source material despite playing a younger version of the character than is seen in the comics, and said her journey in the film begins with the character having been alone for a long time and "running away from her uniqueness".
- The film's first teaser debuted as a post-credits scene for Spider-Man: No Way Home (2021), saying at the end, "Doctor Strange Will Return". A week after the film's release, on December 22, 2021, the teaser trailer was released online but at the end it stated the film's title.
- While Doctor Strange and America are tumbling through several of the universes that make up the multiverse, there's a brief moment where another variation of a New York street is shown, and a taxi cab with the logo "Grindhouse Releasing" is on the roof of the car. Grindhouse is the theatrical distributor for revivals of Sam Raimi's first feature film, The Evil Dead (1981). The company was also co-founded (along with Sage Stallone) by Bob Murawski, who also edited this film as well as Raimi's Spider-Man trilogy.
- Following Scott Derrickson's departure as director, Rachel McAdams initially revealed that she would not reprise her role as Christine Palmer from Doctor Strange (2016). When the film's main cast and director were officially announced at Disney's 2020 Investor Event, it was confirmed that McAdams would indeed return for the film.