- Skurge the Executioner (Only appearance; dies)
- Revengers (Only appearance) (Disbands)
- Loki (Impersonates Odin) (Joins and leaves team)
- Valkyrie / Scrapper 142 (First appearance) (Main story and flashback) (Joins and leaves team)
- Heimdall (Joins and leaves team)
- Korg (First appearance) (Joins and leaves team)
- Miek (First appearance) (Joins and leaves team)
- Hulk (Dr. Bruce Banner) (Joins and leaves team)
- Odin (Death)
- Surtur (First appearance) (Apparent death)
- Hela (First appearance) (Main story and flashback) (Apparent death)
- Grandmaster (First appearance)
- Topaz (First appearance) (Apparent death)
- Draugr Warriors (First appearance)
- Fenris (First appearance) (Resurrection) (Apparent death)
- Ultron Sentries (Mentioned)
- Lady Sif (Mentioned)
- Einherjar (Last appearance) (Death)
- Jane Foster (Mentioned)
- Masters of the Mystic Arts
- Warriors Three (Last appearance)
- Man-Thing (Theodore Sallis) (Statue)
- Beta Ray Bill (Statue)
- Ares (Statue)
- Bi-Beast (Statue)
- Dark-Crawler (Statue)
- Carlo (Grandmaster's cousin) (Only appearance; dies)
- Doug (Only appearance) (Corpse)
- Stan Lee
- Frigga (Drawing)
- Laufey (Drawing)
- Sleipnir (Drawing)
- Avengers (Mentioned)
- Tony Stark (Mentioned)
- Black Widow (Natasha Romanoff) (On-screen)
- Ultron (Mentioned)
Races and Species:
- Asgardians (Main story and flashback)
- Fire Giants
- Fire Demons
- Frost Giants
- Dark Elves (Mentioned)
- Sakaaran Natives
- Numerous unidentified alien species
- Man-Things (Statue)
- Korbinites (Statue)
- Olympians (Statue)
- Asgardian Wolves
- Valkyrior Steeds (Only in flashback)
- Vampires (Mentioned)
- Nine Worlds
- Asgard (Destruction) (Main story and flashback)
- Vanaheim (Mentioned)
- Sakaar (First appearance)
- Sakaar City (First appearance)
- Junk Wastelands (First appearance)
- Sakaarian Ocean (First appearance)
- Devil's Anus (First appearance)
- Xandar (Mentioned)
- Nine Worlds
- Infinity Stones (Mentioned)
- Surtur's Crown (First appearance)
- Mjolnir (Destruction)
- Twilight Sword (First appearance)
- Des & Troy (Skurge's guns) (Only appearance)
- Cloak of Levitation
- Eye of Agamotto
- Crimson Bands of Cyttorak (Cameo)
- Daggers of Daveroth
- Sling Ring
- Necrosword (First appearance)
- Obedience Disk (First appearance)
- Melt Stick (First appearance)
- Infinity Gauntlet (Replica) (Last appearance)
- Casket of Ancient Winters
- Warlock's Eye (Cameo)
- Tuning Fork (Cameo)
- Eternal Flame
- Skurge's Axe (First appearance)
- Dragonfangs (First appearance) (Main story and flashback)
- Warsong (Only appearance; destruction)
- Quinjet (Destruction)
- Topaz's ship (Only appearance; destruction)
- Commodore (First appearance)
- Turano (First appearance)
- Escort (First appearance)
- Kingswood (First appearance)
- The Statesman (First appearance)
- Sanctuary II (Cameo)
Thor has been captured by mysterious enemy forces. He speaks to a skeleton sharing his cage about how he's been looking for the Infinity Stones, with no luck. He says that sometimes you must be captured to get a direct response from someone. That someone turns out to be Surtur. Thor and Surtur begin talking, in which the latter makes fun of him with the knowledge that Odin is no longer in Asgard and that the absence of Thor leaves him vulnerable. He announces that the Ragnarök (the end of Asgard) will come by his hand and there is nothing that Thor can do to stop him, although he foolishly confesses that his crown is the source of his powers.
Thor takes the signal to call Mjolnir, breaking out and fighting Surtur's henchmen before taking his crown as a trophy. When he tries to return to Asgard, Heimdall does not respond. His replacement Skurge notices Thor's call only when one of the women he's trying to impress points to it.
Returning to Asgard, Skurge tells Thor that Heimdall has been declared an enemy of the state and is fleeing. Thor is not impressed and goes to look for Odin, he finds him watching a play about the courageous death of Loki while being pampered by women. In reality, Loki has assumed Odin's appearance. Thor forces him to drop the farce and has Skurge transport him and Loki to Earth to look for Odin, but the asylum where he placed him had been demolished.
At that moment, Loki disappears, leaving a directional card behind him pointing towards the Sanctum Sanctorum where he finds Doctor Stephen Strange. Strange insists on knowing why Loki and Thor are there and if they will leave or not when they finish. Thor tells him that they are there to find Odin and once done, they will leave immediately. Strange reveals that he knows where Odin is, in Norway, and sends Thor and Loki there.
They find Odin being released from the spell that Loki had placed on him, but he is dejected and dying. In his last moments, he makes a confession: Hela, Thor and Loki's unknown sister and Goddess of Death, will be released once he dies. She is much more powerful than her brothers and will become stronger when she returns to Asgard. Odin is transformed into energy and apparently dies.
Almost immediately Hela escapes from her prison and attacks them. Thor throws Mjolnir but she catches it and breaks it in her hand. Loki panics and calls for the Bifrost. However, during their transport, Hela intercepts them, forcing both Thor and Loki out of the beam.
Hela turns her eyes towards Asgard, arriving via Bifrost and easily killing Volstagg and Fandral. She recruits Skurge at her side, almost without effort destroying the entire Asgardian army, leaving Hogun who was the last to fall. She takes the throne and destroys her father's mural on top, revealing the original behind it. In fact, it is revealed that she was always Odin's most powerful weapon, which was used to create the powerful Asgardian empire, and only when her ambition surpassed his did he imprison her.
She bursts into the trophy room, declaring the Infinity Gauntlet as false, the Casket of the Ancient Winters as an unused object, Surtur's crown smaller than she imagined, but interested in the Tesseract. She travels to the mausoleum below, reviving the fallen Asgardian soldiers and their mascot Wolf Fenris, before giving Skurge the title of the Executioner. Meanwhile, Heimdall slips into Bifrost's observatory and steals the sword, rendering it unusable, before organizing a resistance against Hela. Hela, now unable to start her conquest of all the kingdoms, sends new soldiers to hunt this resistance and recover the sword.
Skurge has civilians surrounded and demands the location of the sword. When no one speaks, Hela tells her to execute a woman chosen at random, although Skurge seems to be uncomfortable with this. Just before he can do it, a civilian agrees to tell Hela what he wants to know instead of watching an innocent person die.
Meanwhile, Thor is deposited on an alien planet called Saakar, covered in waste. There are portals from other places throughout the sky, where garbage and debris from other worlds fall to the surface. A woman throws a small disc onto his neck and this allows her to knock him unconscious. With the disc attached to his neck preventing this escape, the woman takes him to the supreme ruler of the planet, the Grandmaster, who seeks to use him as a gladiator in the games to keep him in his power. Due to the unusual relativistic effects of how they got there, Loki has already been there for weeks, winning the favor of the Grandmaster. The Grandmaster tells Thor that he can have his freedom if he defeats the champion of Saakar's arena.
Thor is thrown into the gladiator's quarters where he meets Korg, a Kronan resistance fighter, and his friend Miek. Korg says that nobody has been able to escape or defeat the Grandmaster's champion. Thor is ready to fight this man, having his hair forcibly cut by someone strangely familiar, and choosing his weapons. He finds the woman who captured him, whom he recognizes as an Asgardian Valkyrie. When she does not sympathize with the difficult situation of his home, Thor calls her a coward before being forced to go out and fight.
It is revealed that the Grandmaster's champion is Hulk. Thor, full of joy to see his old partner, tries to talk to him and negotiate with him but he makes the mistake of calling him 'Banner'. He also uses Natasha Romanoff / Black Widow's technique to calm him, but this fails. Hulk begins to gain the upper hand in the battle and is close to killing Thor, but he has a vision of his father, causing his powers to re-emerge. Thor takes the lead, but the Grandmaster, not wanting to see the Hulk lose, being the fan's favorite, throws the fight by activating the disk in Thor's neck, knocking him out.
Thor wakes up in a luxurious room with the Hulk, who refuses to return to Earth as he believes he is hated there and once again refuses to leave. He is shown to be Valkyrie's friend and training partner, and Thor tricks her into coming to her room so that Thor can steal the control device and remove the disk from his neck.
Thor tries to get to the Quinjet that the Hulk brought to Sakaar, but Hulk chases him down, trying to get Thor to stay. They begin to fight, and Thor accidentally triggers a recording of Natasha's attempts to calm Hulk down while flying the Quinjet, which calms him down and transforms him back into Bruce Banner. Banner has been in the form of Hulk for two years, ever since arriving on Sakaar, fearing that if he becomes Hulk again, Banner will disappear forever.
The Grandmaster orders Valkyrie and Loki to track down Thor and Hulk. Valkyrie is knocked out by Loki, who shows her a vision of her and her sisters falling under the hand of Hela millennia ago, leaving her the only survivor. This is what led her to become a bounty hunter on Sakaar. Loki, not wanting to get stuck on Sakaar, finds Thor and tells him that he has the security and control codes of the Grandmaster's systems.
After Thor talks to Heimdall about the situation on Asgard, Valkyrie returns and tells Thor that they need to go through the biggest portal in the sky (unfortunately whose nickname is "The Devil's Anus") to escape. Unfortunately, Valkyrie's ship is not capable for the job. They free Korg and Miek so that they can start a slave revolt as a distraction to get the Grandmaster's personal ship.
Loki, inevitably, betrays them while they are escaping, but Thor has quietly placed one of the discs on his back, leaving him incapacitated on the floor. Thor tells his brother that he knows that Loki will always be the God of Mischief, but hopes that he will show some ability to mature, before leaving (with Loki still shocked and unable to reach the disc's controller). However, Korg arrives with a group of slaves and turns off the device later. Loki takes the leadership of the group, as Korg isn't exactly the leader type, and steals a ship with them.
Thor, Valkyrie and Banner arrive in Asgard after narrowly escaping Sakaar. Hela starts the assault on the fortress where Heimdall is hiding the Asgardian civilians, but Thor calls her to the throne room to fight. Banner and Valkyrie fight to help civilians escape via Bifrost but they are cut from behind by the undead army and from the front by the huge Fenris.
Despite knowing that he may never return, Banner becomes the Hulk to fight Fenris as Loki arrives with Korg and the Sakaarian slaves. Thor is overtaken by Hela who hits him in the face, gouging out his eye. She is too much for him and once again Thor has a vision of his father. He tells her that Asgard's true measure isn't in the place, but the people who live there. Thor says he can not defeat Hela without Mjolnir, but Odin reminds Thor that he is "not the god of hammers" and Mjolnir was always a focus of his powers, which are even greater than those of Odin. Using his powers to the fullest, Thor manages to resist Hela and make his way through her army, but he realizes that this is still too much for him. He and Loki agree that as long as Asgard exists she will become more powerful. However, Thor remembers that Ragnarok, according to prophecy, must come to pass. Asgard must fall, and that he was never meant to stop it, but to help it along. Thor and Valkyrie hold Hela back while Loki goes to the trophy room to retrieve Surtur's crown, spying the Tesseract on the way. He places Surtur's crown in the flames of Asgard and Surtur is resurrected.
The now larger and much more powerful Surtur begins to raze Asgard, with even Hela unable to stop it. She tries to prevent the ship carrying the Asgardian refugees and the Sakaarian slaves from leaving, but Skurge, who has slipped away in disguise, turns against her and fights with her soldiers before he is killed.
Hulk begins to attack Surtur, with the justification that he's usually the one to fight giant monsters, but is called to return. Thor and Valkyrie, aboard the escaping ship, can only watch as Asgard is completely destroyed, leaving only asteroids behind. Thor, who now wears an eye patch like his father, is crowned as the King and decides that they should set course towards Earth to rebuild Asgard, perhaps in Norway, as Odin suggested.
In a post-credits scene, Loki asks Thor if he will be welcome on Earth and Thor assures him that he will be. Thor is sure everything will be fine, but a much, much larger ship appears behind them. In the second post-credits scene, the Grandmaster is accosted by the slaves he had been in control of. He tries to declare the revolt as 'a draw,' trying to save his own skin, but they are not impressed.
Additionally, Benedict Cumberbatch reprises the role of Doctor Strange, after debuting in a standalone film. Taika Waititi, the film's director, does the motion-capture and voice of Korg. Rachel House appears as Topaz Clancy Brown provides the voice of Surtur, whom Waititi also provides the motion-capture for. Tadanobu Asano, Ray Stevenson, and Zachary Levi reprise their roles as the Warriors Three Hogun, Volstagg, and Fandral, respectively. Luke Hemsworth and Sam Neill make cameo appearances as Actor Thor and Actor Odin, respectively. Charlotte Nicdao portrays Actor Sif. Steven Oliver portrays Cousin Carlo. Matt Damon makes an uncredited cameo as Actor Loki.
- The title of the film was revealed during Marvel Studios' event at El Capitan Theatre on October 28, 2014.
- The original release date for Thor: Ragnarok was July 28, 2017, but was pushed back and Spider-Man: Homecoming took its slot.
- Natalie Portman and Jaimie Alexander did not reprise their roles as Jane Foster and Lady Sif, respectively, from the previous two Thor films. Writer Eric Pearson said that the exclusion of human supporting characters was to give more time to develop Sakaar and Valkyrie. Additionally, Alexander claims that Marvel Studios didn't give her enough time to schedule filming around her TV series Blindspot.
- According to herself, writer Stephany Folsom, who had joined the movie in pre-production to polish the script, was denied a "Story by" credit by the Writers Guild of America due to their regulations, despite Marvel Studios' intention to give her credit.
- A scene from Thor: Ragnarok depicting Thor meeting Doctor Strange was included as a mid-credits scene in the film Doctor Strange.
- Jeff Goldblum as the Grandmaster made a cameo appearance during the end credits of the film Guardians of the Galaxy Vol. 2.
- With a worldwide total box office gross of about $853 million, this film became the 9th-highest-grossing film of 2017.
- The song "Immigrant Song" by Led Zeppelin, which was used prominently in the film's marketing, was used in the film's first and last action sequences. The song heavily alludes to Norse mythology. Director Taika Waititi believes that using the song in his initial sizzle reel is what got him hired.
- The shake weight Skurge uses in the film belongs to Waititi, who bought it while filming Green Lantern.
- A preliminary idea had the film take place mostly in Valhalla. According to Taika Waititi, that idea "only lasted a couple of weeks."
- In the play Loki puts on in Asgard, it is revealed that Loki once turned Thor into a frog. This is a reference to the brief run in comics where Thor was a frog and to the character Throg.
- Thor holding Loki's head in the path of his returning hammer is taken almost directly from a sequence in Thor #359.
- Shady Acres, the destroyed nursing home Odin was residing in, is a nursing home that has appeared in multiple media, most notably on the television series South Park and the film Ace Ventura: Pet Detective.
- While in mortal disguise, Thor's hammer Mjolnir is disguised as an umbrella. Later in the film, Thor taps it on the ground to revert back to wearing his Asgardian armor. This could be an homage to his early days in the comics, where he'd tap his walking stick on the ground to the same effect.
- Doctor Strange's presence in the movie was decided even before Taika Waititi was brought to direct the film. Before Marvel settled on his role as a minor guest star, Strange was tentatively going to be Thor's partner in his journey, until they decided on the Hulk.
- Originally, Thor and Loki find Odin living in the streets of New York. This was changed after test audiences felt his death in that context was too depressing.
- In early scripts of the movie, Thor would find that Hela is her sister later on. Waititi opted to "get it out of the way early" in part because he felt it was pointless to try to "compete" with the reveal of Luke Skywalker's parentage in Star Wars: Episode V - The Empire Strikes Back. He also argued that it was not the most important revelation of the movie, and that it actually helped the plot if Thor knew early on.
- The scene of Mjolnir's destruction at the hands of Hela originally took place in an alleyway in Manhattan, as evidenced by the film's first trailer. For the final cut of the movie, it was changed to an open field in Norway. Waititi explained the setting was changed because he felt the city was a terrible environment for such emotional scene, and additionally to help the pacing of the movie.
- Valkyrie actress Tessa Thompson has commented that her character is bisexual. She also mentioned she had convinced Waititi to shoot a scene with a glimpse of a woman walking out of Valkyrie's bedroom. He kept it in the film as long as he could, but eventually cut it because it distracted from the scene's vital exposition. Thompson also commented that in her mind, one of the members of Valkyrie's warrior clan was her lover.
- Among the statues that commemorate the previous champions of the Grandmaster's contest are the busts of Beta Ray Bill, Man-Thing, Ares, Dark-Crawler and Bi-Beast.
- A planned Beta Ray Bill cameo was scrapped because Kevin Feige felt it wouldn't do the character justice.
- The song "Pure Imagination" from Willy Wonka & the Chocolate Factory plays in the background of the scene where Thor is given a background on the Grandmaster. The scene also resembles the trippy boat ride scene from the same film.
- Valkyrie's alias in Sakaar, Scrapper 142, is probably a reference to the character Samantha Parrington's first appearance as Valkyrie in Incredible Hulk #142.
- The Grandmaster's Contest of Champions is named after Marvel Super Hero Contest of Champions, in which the Grandmaster plays a key role.
- The film has a few notable callbacks to previous Marvel Cinematic Universe films.
- The "adopted brother" joke from Marvel's The Avengers is repeated, but with Loki claiming to be the adopted one this time.
- Black Widow's "the sun is getting real low," line from Avengers: Age of Ultron is brought up again when Thor tries to calm Hulk down in the arena.
- Hulk smashes Thor on the ground the same way he smashed Loki in Marvel's The Avengers. Loki even revels in watching Thor getting smashed in the same manner.
- Thor's identification code in the Avengers quinjet being "Point Break" is a callback to the nickname Tony Stark gave him in Marvel's The Avengers. The nickname itself is a reference to the film Point Break.
- Bruce failing to turn into the Hulk after jumping out of an aerial vehicle could be a callback to a similar effort made by him in The Incredible Hulk.
- According to screenwriter Eric Pearson, Thor's haircut served another purpose in addition to symbolizing Thor's journey, it also prevented Chris Hemsworth from having to wear a wig, which he used to find annoying due to how much time it took to get it right.
- A rebuilt Destroyer Armor was almost featured in the movie, in a scene where it would've tried and miserably failed to stop Hela in Odin's vault. Eric Pearson mentioned the scene was scrapped as it felt unnecessary and slowed down the progress of the story.
- The story about Loki stabbing Thor after disguising himself into a snake was partially improvised. Waititi fed Hemsworth ideas for stories until they settled on the snake story. One of the scrapped versions had Loki shapeshift into a Turkish rug in the middle of a field, prompting Thor to stand on it since he liked them. Loki would then turn back into Loki, revealing a hole in the ground with spikes in the bottom that Thor would have fallen into.
- Thor and Loki's "get help" scene wasn't originally in the script. Chris Hemsworth and Tom Hiddlestone came up with it on the day the scene was shot.
- Before settling on having Bruce Banner fall on his face at the Bifrost, there was going to be a scene of the Revengers landing next to each other. Hulk and Loki would land next to each other, and after a second, Hulk would've punched him out of the frame, mirroring a similar scene between Thor and Hulk during the final battle of Marvel's The Avengers.
- A few versions of the movie's plot had Thor prevent Asgard's destruction.
- According to himself, for preparation to direct the movie, Taika Waititi only read one Thor comic book, which impulsed him to take the characters to another direction.