Skuespillere i Transformers II: * Shia LaBeouf plays Sam Witwicky, the teenager who killed Megatron. He attends an East Coast college to learn astronomy.
* Megan Fox plays Mikaela Banes, Sam's girlfriend, who cannot afford to attend college with him. Fox had lost much weight for her role in Jennifer's Body, and had to gain ten pounds within three weeks. She explained "Michael [Bay] doesn't like skinny girls."
* Josh Duhamel plays Captain William Lennox, an ally of the Autobots. Since the first film Lennox has become part of an international taskforce battling Decepticons with the Autobots.
* Tyrese Gibson plays Air Force Technical Sergeant Robert Epps, an ally of the Autobots and member of Lennox's team.
* John Turturro plays Reggie Simmons, former agent of the terminated Sector 7 unit, which monitored the Transformers activity on Earth.
* Matthew Marsden plays Graham, a member of the United Kingdom Special Forces who joins Lennox's team. Marsden grew up reading the comic book and loved the first film. Bay was impressed with his audition and decided to increase the character's screentime.
* Isabel Lucas plays Alice, a new character who goes to Sam's college.
* Ramon Rodriguez plays Leo.
* Steve Tom has a "principal" role, according to his website.
* Kevin Dunn and Julie White play Ron and Judy, Sam's parents. Orci wrote, "Love them! Gotta have them back." He confirmed they learned the truth about the Transformers while off-screen in the last film.
Rainn Wilson cameos as a university professor, while Kym Whitley has an unnamed part.
- Så der er både lidt gammelt og lidt nyt.

Men er selv meget ked af Anthony Andersons figur computernørden Glen ikke er med, han gav ellers nolge gode grin
