Tim Roth as Emil Blonsky: A former Russian-born officer in the United Kingdom's Royal Marines Commandos, who was on loan to help Thaddeus Ross capture Banner and the U.S. Secretary of State who helps the Avengers fight Thanos.
Mark Wingert as Tony Stark / Iron Man: The benefactor of the Avengers who is a self-described genius, billionaire, playboy, and philanthropist with electromechanical suits of armor of his own making.
Chris Hemsworth as Thor: An Avenger and the king of Asgard, based on the Norse mythological deity of the same name.
Mark Ruffalo as Bruce Banner / Hulk: An Avenger and genius scientist who, because of exposure to gamma radiation, typically transforms into a monster when enraged or agitated.
Josh Keaton as Steve Rogers / Captain America: The fugitive leader of the non-regulation faction of Avengers. A World War II veteran, he was enhanced to the peak of human physicality by an experimental serum and frozen in suspended animation before waking up in the modern world.
Lake Bell as Natasha Romanoff / Black Widow: A highly trained spy, member of Rogers' faction of Avengers, and former agent of S.H.I.E.L.D.
Benedict Cumberbatch as Dr. Stephen Strange / Doctor Strange: A former neurosurgeon who, after a car accident that led to a journey of healing, discovered the hidden world of magic and alternate dimensions and became a Master of the Mystic Arts.
Don Cheadle as James "Rhodey" Rhodes / War Machine: An officer in the U.S. Air Force and Avenger who operates the War Machine armor.
Hudson Thames as Peter Parker / Spider-Man: A teenager, Avenger and Stark's protégé who received spider-like abilities after being bitten by a radioactive spider.
Chadwick Boseman as T'Challa / Black Panther: The king of the African nation of Wakanda who gained his enhanced strength by ingesting the Heart-Shaped Herb.
Paul Bettany as Vision: An android and Avenger created using the artificial intelligence J.A.R.V.I.S., Ultron, and the Mind Stone.
Elizabeth Olsen as Wanda Maximoff: A member of Rogers' faction of Avengers who can harness magic and engage in hypnosis and telekinesis.
Anthony Mackie as Sam Wilson / Falcon: A member of Rogers' faction of Avengers and former pararescueman trained by the military in aerial combat using a specially designed wing pack.
Sebastian Stan as Bucky Barnes / White Wolf: An enhanced soldier and Rogers' ally and best friend who reemerged as a brainwashed assassin after being thought to have been killed in action during World War II. Barnes, formerly known as the Winter Soldier, is given the name White Wolf by the people of Wakanda, who helped remove his Hydra programming.
Tom Hiddleston as Loki: Thor's adopted brother, based on the Norse mythological deity of the same name.
Idris Elba as Heimdall: The all-seeing, all-hearing Asgardian and former sentry of the Bifröst Bridge, based on the Norse mythological deity of the same name.
Peter Dinklage as Eitri: King of the Dwarves of Nidavellir, and weaponsmith, based on the Norse mythological dwarf of the same name.
Benedict Wong as Wong: A Master of the Mystic Arts, tasked with protecting some of Kamar-Taj's most valuable relics and books.
Pom Klementieff as Mantis: A member of the Guardians with empathic powers.
Karen Gillan as Nebula: An adopted daughter of Thanos who was raised with Gamora as siblings.
Fred Tatascoire as:
Drax the Destroyer: A member of the Guardians and warrior in search of vengeance against Thanos for killing his family.
Corvus Glaive: A member of the Children of Thanos, who wields a glaive.
Cynthia McWilliams as Gamora: A member of the Guardians who is an orphan from an alien world and was subsequently raised by Thanos, and is seeking redemption for her past crimes. Ariana Greenblatt voices a young Gamora.
Vin Diesel as Groot: A member of the Guardians who is a tree-like humanoid.
Bradley Cooper as Rocket: A member of the Guardians who is a genetically-engineered raccoon-based bounty hunter, mercenary, and master of weapons and battle tactics.
Beth Hoyt as Pepper Potts: Stark's fiancée and the CEO of Stark Industries.
Benicio del Toro as Taneleer Tivan / The Collector: One of the Elders of the Universe who is an obsessive keeper of the largest collection of interstellar fauna, relics, and species of all manner in the galaxy.
Josh Brolin as Thanos: An intergalactic warlord from Titan who seeks all six Infinity Stones to destroy half of all life for the sake of "re-balancing the universe".
Brian T. Delaney as Peter Quill / Star-Lord: The half-human, half-Celestial leader of the Guardians who was abducted from Earth as a child and raised by a group of alien thieves and smugglers called the Ravagers.
Danai Gurira as Okoye: The general of the Dora Milaje.
Okioma Akagha as Shuri: The princess of Wakanda and T'Challa's sister, who develops their technology.
Kerry Condon as F.R.I.D.A.Y.: Stark's artificial intelligence.
Winston Duke as M'Baku: The leader and general of the Jabari Tribe.
Florence Kasumba as Ayo: A member of the Dora Milaje.
Jacob Batalon as Ned Leeds: Parker's best friend and "guy in the chair".
Isabella Amara as Sally Avril: Parker's classmate.
Cindy Moon: Parker's classmate.
Tiny McKeever: Parker's classmate.
Samuel L. Jackson as Nick Fury: The former director of S.H.I.E.L.D.
Cobie Smulders as Maria Hill: The former deputy director of S.H.I.E.L.D., who used to work for Stark.
Michael Douglas as Hank Pym: An entomologist, physicist, and former S.H.I.E.L.D. who discovered the Pym Particles in the 1970s.
Michelle Pfeiffer as Janet van Dyne: Hank's wife, who was trapped in the Quantum Realm for 30 years.
Evangeline Lilly as Hope van Dyne / Wasp: Hank and Janet's daughter and Scott's girlfriend, who took the Wasp mantle from her mother.
Paul Rudd as Scott Lang / Ant-Man: A former petty criminal who acquired the Ant-Man suit and can grow and shrink at well, while maintaining all of his regular strength.
Alexandra Daniels as Carol Danvers / Captain Marvel: A former USAF pilot and Kree-human hybrid who gained superhuman abilities, such as superhuman strength, speed, flight, and energy absorption after absorbing a blast from the Tesseract.
Terry Notary as Cull Obsidian: A member of the Children of Thanos, who wields a hammer.
Tom Vaughan-Lawlor as Ebony Maw: A member of the Children of Thanos, who uses dark magic and sorcery.
Carrie Coon as Proxima Midnight: A member of the Children of Thanos, who wields a spear.
Ross Marquand as Johann Schmidt / Red Skull: The former World War II Nazi lieutenant and the Soulkeeper of the Soul Stone.
Stan Lee as himself: A school bus driver.
Kenneth Branagh as Asgardian distress caller: An Asgardian distress caller.