Transformers: Dark of the Moon is a 2011 American science fiction action film based on Hasbro's Transformers toy line. The film is the third installment in the Transformers film series and the sequel to Transformers: Revenge of the Fallen (2009). The film is directed by Michael Bay and written by Ehren Kruger. It stars Shia LaBeouf, Josh Duhamel, John Turturro, Tyrese Gibson, Rosie Huntington-Whiteley, Patrick Dempsey, Kevin Dunn, Julie White, John Malkovich, and Frances McDormand. The story revolves around Optimus Prime, Sam Witwicky, and the Autobots as they face off against Sentinel Prime, the first leader of the Autobots who has betrayed them and joined forces with Megatron and the Decepticons. Their plan is to seize powerful technology left behind on the Moon, intending to use it to restore Cybertron to its former glory on Earth.

Development on a third Transformers film began by May 2007. The film employed both regular 35 mm film cameras and specially-developed 3D cameras, with filming locations in Chicago, Florida, Indiana, Milwaukee, Moscow, and Washington, D.C. The film was 3D rendered specifically for 3-D, and the visual effects involved more complex robots which took longer to render. Dark of the Moon's release date was moved from July 1 to June 29, in order to monitor an early response to footage.

Exclusive early premieres took place on June 28, 2011, one night before worldwide release. The film received mixed reviews from critics, with praise for the score, visual effects, cast and voice performances, but was criticized for its screenplay and runtime. Dark of the Moon grossed $1.124 billion worldwide, becoming the fifth highest-grossing film in history at the time, the second highest-grossing film of 2011, and the highest-grossing film in the franchise to date. Like the first film, it was nominated for Best Sound Editing, Best Sound Mixing, and Best Visual Effects at the 84th Academy Awards. It was followed by Transformers: Age of Extinction in 2014.