Avengers: Doomsday is almost here, and Marvel Studios is preparing one of the biggest crossovers in MCU history. The movie arrives in theaters on December 18, 2026, bringing together the Avengers, the Fantastic Four, the New Avengers and characters from the original X-Men movie universe, with Robert Downey Jr. taking on the role of Victor von Doom. That enormous collection of characters also creates a problem for anyone who has fallen behind on Marvel: what exactly do you need to watch before Doomsday? Fortunately, watching every MCU movie and Disney+ series is not necessary. This guide breaks down the movies and shows most likely to matter, why each one is important and where you can stream them before heading to the theater.
1. Avengers: Infinity War
Where to watch: Disney+
Avengers: Infinity War is the best place to begin if you already understand the basic MCU characters. The movie establishes the scale of an Avengers-level threat and brings almost every major hero of the Infinity Saga together against Thanos. More importantly for Doomsday, it establishes the relationships between heroes such as Thor, Doctor Strange and the original Avengers before everything changes. Robert Downey Jr.’s Tony Stark is also central to the story, making Infinity War important context for audiences preparing to see the actor return to Marvel in an entirely different role as Doctor Doom. The movie is currently available on Disney+.
2. Avengers: Endgame
Where to watch: Disney+
If there is one movie that should be considered absolutely essential before Avengers: Doomsday, it is Avengers: Endgame. The conclusion of the Infinity Saga permanently changes the MCU, ends Tony Stark’s story, changes the status of Steve Rogers and establishes the world that every subsequent Marvel project inherited. It is also directly connected to the MCU’s growing exploration of alternate timelines, since the Avengers travel through different points in history while attempting to reverse Thanos’ victory. Understanding where the Avengers were left after Endgame will make the formation of the teams appearing in Doomsday considerably easier to follow.
3. Loki – Seasons 1 and 2
Where to watch: Disney+
Technically this is a series rather than a movie, but Loki may be one of the most useful Marvel projects to watch before Doomsday. The series takes place after the events of Endgame and dramatically expands Marvel’s rules surrounding timelines, variants and alternate realities. Season 2 pushes those concepts even further, with Loki traveling through collapsing timelines as the TVA faces a potentially catastrophic situation. With Doomsday positioned within the Multiverse Saga, understanding how Marvel has treated branching realities and timelines could make the larger conflict much easier to understand. Both seasons are available on Disney+.
4. Doctor Strange in the Multiverse of Madness
Where to watch: Disney+
Doctor Strange in the Multiverse of Madness is another important piece of preparation because it introduces audiences to the destructive consequences that can occur when different universes collide. Doctor Strange travels across alternate realities with America Chavez, while the movie develops the concept of incursions, events capable of threatening entire universes. That concept could become increasingly important as Marvel’s Multiverse Saga approaches its conclusion. The movie also demonstrates that different versions of familiar Marvel characters can exist across separate realities, something audiences should be comfortable with before entering a movie containing characters from several different corners of Marvel history. Disney+ lists the film as part of its MCU library.
5. Deadpool & Wolverine
Where to watch: Disney+
Deadpool & Wolverine is particularly valuable because it directly connects the MCU with Marvel characters originating outside its original continuity. Wade Wilson becomes involved with the TVA and is forced into a mission involving different realities, while Hugh Jackman returns as Wolverine. The movie helps audiences understand how Marvel can incorporate characters and universes from its pre-MCU movie history into the larger Multiverse Saga. That becomes especially relevant for Doomsday because actors associated with the original X-Men films are part of the movie’s enormous ensemble. Deadpool & Wolverine is currently streaming on Disney+.
6. X-Men
Where to watch: Disney+
The original X-Men from 2000 suddenly matters again. Patrick Stewart, Ian McKellen, James Marsden, Alan Cumming, Rebecca Romijn and Kelsey Grammer are among the veteran X-Men performers connected to Doomsday, making the original Fox universe relevant to Marvel’s next Avengers crossover. The first X-Men movie introduces Professor Charles Xavier, Magneto, Cyclops, Storm and Wolverine while establishing the fundamental conflict between humans and mutants. For viewers unfamiliar with the original franchise, this is the simplest starting point. The movie is currently available through Disney+ in Brazil.
7. X2: X-Men United
Where to watch: Disney+
If you have additional time, continue directly into X2: X-Men United. The sequel expands the original mutant team and introduces Nightcrawler, played by Alan Cumming, while developing the relationship between Professor X, Magneto and the X-Men. That makes X2 especially relevant when preparing for Doomsday’s returning mutant characters. Disney+ currently carries the film, alongside other entries from the original X-Men franchise.
8. X-Men: The Last Stand
Where to watch: Disney+
X-Men: The Last Stand completes the original X-Men trilogy and adds another character particularly relevant to Doomsday: Kelsey Grammer’s Beast. The film follows the X-Men as they confront the return of Jean Grey and an escalating conflict surrounding a supposed mutant cure. While watching every Fox X-Men movie is unnecessary, completing this original trilogy provides considerably more context for the legacy characters Marvel is bringing back. The movie is available on Disney+.
9. Captain America: Brave New World
Where to watch: Disney+
After Steve Rogers’ departure, Sam Wilson is now Captain America, and Captain America: Brave New World establishes his position within the modern MCU. The movie follows Sam after he becomes caught in an international conspiracy involving U.S. President Thaddeus Ross. For viewers who stopped following Marvel after Endgame, this movie provides useful context for how dramatically the MCU’s political and superhero landscape has changed. Disney+ currently offers Brave New World for streaming.
10. Thunderbolts*
Where to watch: Disney+
Thunderbolts* becomes extremely important because it establishes another major superhero group in the MCU. The movie brings together Yelena Belova, Bucky Barnes, Red Guardian, Ghost, John Walker and other characters as an unconventional team of antiheroes. Their story represents one of the clearest bridges between Marvel’s post-Endgame projects and the massive ensemble being assembled for Doomsday. Anyone wanting to understand the current state of Marvel’s superhero teams should put this near the top of the watchlist. Thunderbolts* is currently streaming on Disney+.
11. The Fantastic Four: First Steps
Where to watch: Disney+
This is another must-watch before Avengers: Doomsday. The Fantastic Four: First Steps introduces the MCU versions of Reed Richards, Sue Storm, Johnny Storm and Ben Grimm, played by Pedro Pascal, Vanessa Kirby, Joseph Quinn and Ebon Moss-Bachrach. The movie takes place in its own retro-futuristic world and establishes Marvel’s First Family before their involvement in the larger crossover. Because the Fantastic Four are directly connected to Doomsday, skipping their introduction means entering the Avengers movie without understanding an entire central group of characters. First Steps is now streaming on Disney+.
Bonus: Fantastic Four (2005)
Where to watch: Disney+
The 2005 Fantastic Four is not required viewing, because its version of the team is separate from the Fantastic Four introduced in First Steps. However, it offers an accessible introduction to one character who matters enormously to Doomsday: Victor von Doom. Julian McMahon plays that movie’s version of Doom, providing audiences unfamiliar with Marvel Comics with a basic understanding of the character’s history with Reed Richards and the Fantastic Four. Robert Downey Jr.’s Doctor Doom is a different interpretation, so the film should be treated as optional background rather than direct MCU continuity. It is currently available on Disney+.
The Short Version: What You Absolutely Need to Watch
If you do not have time for everything, prioritize Avengers: Infinity War, Avengers: Endgame, Loki Seasons 1 and 2, Deadpool & Wolverine, X-Men, Thunderbolts* and The Fantastic Four: First Steps. That selection covers the fall of the original Avengers, Marvel’s multiverse and timeline concepts, the return of the Fox-era Marvel universe, the New Avengers and the introduction of the Fantastic Four. Most of the recommended titles are conveniently available in one place: Disney+ currently carries MCU films including Infinity War, Endgame, Deadpool & Wolverine, Brave New World, Thunderbolts* and First Steps, alongside older Marvel movies such as X-Men and its sequels. Availability can vary by country and change over time.
FAQ
Do I need to watch every Marvel movie before Avengers: Doomsday?
No. Watching the entire MCU would provide additional context, but it should not be necessary. Focusing on the Avengers, multiverse, Fantastic Four, New Avengers and relevant X-Men stories provides a much shorter preparation route.
What is the most important movie to watch before Avengers: Doomsday?
Avengers: Endgame is the strongest starting point because it establishes the aftermath of the original Avengers era and directly leads into the MCU’s post-Infinity Saga status quo.
Should I watch Loki before Avengers: Doomsday?
Yes. Although it is a Disney+ series, Loki is highly recommended because its two seasons explore the TVA, alternate timelines and the structure of Marvel’s increasingly complicated multiverse.
Do I need to watch the old X-Men movies?
Not all of them. X-Men (2000), X2 and X-Men: The Last Stand provide a compact introduction to several legacy mutant characters. All three are available through Disney+ in Brazil.
Do I need to watch the old Fantastic Four movies?
No. The Fantastic Four: First Steps is the important movie because it introduces the Fantastic Four relevant to the current MCU storyline. The 2005 movie is optional background for viewers interested in Doctor Doom.
Where can I watch the movies before Avengers: Doomsday?
Disney+ currently carries most of the essential Marvel movies and shows in this guide, including Infinity War, Endgame, Loki, Deadpool & Wolverine, X-Men, Thunderbolts* and The Fantastic Four: First Steps. Streaming availability can vary by region.
