Shia LaBeouf, Josh Duhamel, Tyrese Gibson, and John Turturro reprised their starring roles, with Peter Cullen and Hugo Weaving returning as the voices of Optimus Prime and Megatron, and Kevin Dunn and Julie White reprising their roles as the parents of the main protagonist, Sam Witwicky. English model Rosie Huntington-Whiteley replaced Megan Fox as the lead female character; the cast also saw the additions of Patrick Dempsey, John Malkovich, Ken Jeong, and Frances McDormand. Leonard Nimoy, Keith Szarabajka, Ron Bottitta, John DiMaggio, George Coe, Francesco Quinn, James Remar, and Greg Berg had joined the film's voice cast. The script was written by Ehren Kruger, who also collaborated on the narrative of the second film of the series. Bay has stated this would be his last installment in the series. Dark of the Moon was shot with both regular 35mm film cameras and specially developed 3-D cameras, with filming locations including Indiana, Washington, D.C., Moscow, Florida, and Chicago. The film was rendered specifically for 3-D, and the visual effects involved more complex robots which took longer to render.
In May 2011, it was announced that Paramount Pictures moved Transformers: Dark of the Moon's release date of July 1, 2011, to June 29, in order to receive an early response to footage. The film was then released nationwide one day earlier, June 28, in selected 3-D and IMAX theaters, to open exclusively one night before its official global release, and one day later in wide release, in both, 2-D and 3-D formats, including IMAX 3D, and featuring Dolby Surround 7.1 sound.
Critical reception of the film was mixed to negative, with several critics calling it better than Revenge of the Fallen and praising the film's visuals and 3-D action sequences, but criticizing its writing, acting, and length. Dark of the Moon grossed $1.12 billion worldwide, and is currently the fourth highest-grossing film of all time, the second highest grossing film of 2011 (behind Harry Potter and the Deathly Hallows – Part 2), the highest grossing film in the Transformers series, and the tenth film to gross over $1 billion.
In 1961, the Ark, a Cybertronian spacecraft carrying an invention capable of ending the war between the philanthropic Autobots and the malevolent Decepticons, crash lands on the dark side of Earth's Moon. The crash is detected on Earth by NASA, and President John F. Kennedy authorizes a mission to put a man on the Moon as a cover for investigating the craft. In 1969, the crew of Apollo 11 lands on the Moon.
In the present, the Autobots assist the United States military in preventing conflicts around the globe. During a mission to Chernobyl, to investigate suspected alien technology, Optimus Prime – the valiant leader of the Autobots – finds a fuel cell from the Ark, discovering that it had survived its journey from Cybertron. The Autobots are attacked by Shockwave, who manages to escape. After learning of the top-secret mission to the Moon, the Autobots travel there to explore the Ark. They discover a comatose Sentinel Prime – Optimus' predecessor as leader of the Autobots – and the Pillars he created as a means of establishing a Space Bridge between two points to teleport matter. After returning to Earth, Optimus uses the energy of his Matrix of Leadership to revive Sentinel Prime.
Meanwhile, Sam Witwicky is frustrated that he is unable to work with the Autobots and is failing to find a job. He also becomes envious of the close relationship between his new girlfriend, Carly Spencer, and her boss Dylan Gould. After finding work, Sam is provided information by his eccentric co-worker Jerry Wang about the Ark, before Jerry is assassinated by the Decepticon Laserbeak. Sam contacts the now-independently wealthy Seymour Simmons, and together they realize that the Decepticons and their leader, Megatron, are murdering people connected to the American and Russian space missions to the Ark. They locate two surviving Russian cosmonauts, who reveal satellite photos of hundreds of Pillars being stockpiled on the Moon. Sam realizes that the Decepticons raided the Ark long before the Autobots' mission and intentionally left Sentinel and five Pillars behind to lure the Autobots into a trap – Sentinel being the key to activating the Pillars and the Decepticons lacking the means to revive him. The Autobots rush to return Sentinel to their base for protection but Sentinel betrays them and kills the Autobot Ironhide, revealing he had made a deal with Megatron to ensure the survival of the Cybertronian race.
Sentinel uses the Pillars to transport hundreds of concealed Decepticons from the Moon to Earth, and Carly is captured by Gould, who is revealed to be in the service of the Decepticons. The Autobots are exiled from Earth at the demand of the Decepticons to avoid war, but as their ship leaves Earth it is destroyed by Megatron's second-in-command, Starscream, seemingly killing the Autobots. The Decepticons, led by Megatron and Sentinel, seize Chicago as their agents place Pillars around the world. Gould reveals to Carly that the Decepticons plan to transport their homeworld of Cybertron to the Milky Way, then to enslave humanity and use Earth's resources to rebuild their world. Sam teams with USAF Chief Robert Epps to go into Chicago to save Carly, but they are nearly killed by Decepticon forces before the Autobots intervene, revealing they concealed themselves during the launch of their ship to convince the Decepticons they were destroyed.
Working together, the Autobots and human soldiers manage to rescue Carly and destroy Laserbeak, Soundwave, Barricade, Starscream, and Shockwave, with Optimus using Shockwave's arm-cannon to blast the Control Pillar, disabling the Space Bridge. Sam confronts Gould as he reactivates the Control Pillar, and knocks Gould into the Pillar, fatally electrocuting him. Bumblebee and Ratchet arrive and destroy the Control Pillar, permanently disabling the Bridge and causing the partially transported Cybertron to implode. Optimus and Sentinel fight while Carly convinces Megatron that he will be replaced as leader of the Decepticons by Sentinel. Sentinel severs Optimus' right arm, and is about to execute him when Megatron intervenes, incapacitating Sentinel. Megatron invokes Optimus for a truce, having the desire to become the one-in-charge again. Optimus attacks Megatron, knowing Megatron's true intentions, decapitating and killing him. Sentinel pleads for his life but Optimus executes him too, for betraying his own principles. With the Decepticons defeated, Carly and Sam are reunited and the Autobots accept that with Cybertron gone, Earth is now their home.
- Shia LaBeouf as Sam Witwicky
- Rosie Huntington-Whiteley as Carly Spencer
- Tyrese Gibson as USAF Chief Robert Epps
- Josh Duhamel as U.S. Army Lt. Colonel William Lennox
- John Turturro as Seymour Simmons
- Patrick Dempsey as Dylan Gould
- Kevin Dunn as Ron Witwicky
- Julie White as Judy Witwicky
- John Malkovich as Bruce Brazos
- Frances McDormand as Charlotte Mearing
- Lester Speight as Hardcore Eddie
- Alan Tudyk as Dutch
- Ken Jeong as Jerry "Deep" Wang
- Glenn Morshower as General Morshower
- Ravil Isyanov as Alexi Voskhod
- Don Jeanes as Neil Armstrong (1969)
- Cory Tucker as Buzz Aldrin (1969)
- Buzz Aldrin as himself
- Bill O'Reilly as himself
- Walter Cronkite as himself (archive footage)
- Peter Cullen as Optimus Prime
- Leonard Nimoy as Sentinel Prime
- Jess Harnell as Ironhide
- Robert Foxworth as Ratchet
- James Remar as Sideswipe
- Francesco Quinn as Dino/Mirage
- George Coe as Que/Wheeljack
- Tom Kenny as Wheelie
- Reno Wilson as Brains
- Ron Bottitta as Amp/Roadbuster
- John DiMaggio as Target/Leadfoot
- Hugo Weaving as Megatron
- Charlie Adler as Starscream
- Frank Welker as Shockwave/Soundwave/Barricade
- Keith Szarabajka as Laserbeak
- Greg Berg as Igor
- Jim Wood as Crowbar
- "Long Haul"
- When Optimus dropped his Shield to look at the sphere, next scene, the shield is gone.
- The Energon sword is in Optimus' arm but the next scene, he was holding the sword.
- Bumblebee caught Sam and Lennox after they killed Starscream but then somehow captured.