Ultra Magnus is a fictional character from the Transformers franchise. Ultra Magnus is based on the Diaclone figure Powered Convoy, which is a modified version of the preexisting Battle Convoy figure. He is usually depicted as a car carrier that converts into a robot. Sometimes the tractor can detach from the trailer and convert into a white version of Optimus Prime, while the trailer can convert into armor that covers the inner robot.

Despite his incredible fighting skills, courage, and unmatched talent for improvisation on the battlefield, Ultra Magnus is not portrayed as a natural leader and displays discomfort if the Autobot Matrix of Leadership should ever find itself placed upon him.

In Generation One, Ultra Magnus is a commander of the Wreckers (Transformers), and his reluctance to change ensures that he expends all options before accepting the idea that he is required to lead. As a leader, Magnus is resolute, fair, and courageous, ever-ready to sacrifice himself for the greater good of his companions and mission, and unyielding in preparation for the protection of those under his command. Although not interested in overall command, Ultra Magnus was the City Commander for Autobot City in The Transformers: The Movie. His toy also featured him in the role of City Commander (a title also held by his original opposite number, the Decepticon leader Galvatron), which indicates that he at least is willing to accept a leadership role in a smaller capacity rather than as supreme commander, a role filled by both Optimus Prime and, later, Rodimus Prime.

Ultra Magnus is armed with missile launchers capable of hitting a target 30 miles away and transforms into a car carrier able to transport his fellow Autobot troops.

From the secret files of Teletraan II: Ultra Magnus is the most mature spokesman for the Autobot cause. As a soldier, he is always practical and serious. And he is so loved by his fellow Autobots that Wheelie and Daniel traveled millions of miles to the Autobot records asteroid, just so they could find out Ultra Magnus's birthday. In his vehicle mode, Ultra Magnus is an armored transport truck, a machine with magnificent fighting skills. His enemies, the Decepticons, respect his courage, but most of all, they fear Ultra Magnus's spirit of self-sacrifice. He always thinks first of the welfare of his fellow Autobots and his mission.

Ultra Magnus makes his first appearance in the Japan-exclusive Transformers: Scramble City (1986). Scramble City never made it to the United States, so most Americans did not see him until the 1986 animated film.

Ultra Magnus made his first continuity appearance in the Earth year 2005 as commander of Autobot City on Earth. Leading the defense of the city when it came under the Decepticon attack, Magnus suddenly found himself commanding the entire Autobot army when Optimus Prime died after his fight with Megatron and passed the Matrix of Leadership to him despite his protestations. Subsequently, in a confrontation with the Decepticons on the planet of Junk, Magnus was blown apart and lost the Matrix to Galvatron, but was reassembled and reactivated by the Junkions. When Hot Rod recovered the Matrix from Galvatron and became Rodimus Prime, Ultra Magnus decided to step down as leader to give the role to Rodimus, but continued to act as his friend and advisor, keeping him on the straight and narrow and always reassuring him, attempting to urge him out of the shadow of Optimus Prime.

Magnus has his share of personal adventures in 2006, such as when he was captured by a Quintesson scientist for study, along with the Wreck-Gar, Marissa Faireborn and Cyclonus; he and Cyclonus developed a mutual, grudging respect for each other as warriors during the ensuing events, as they worked together to escape a negative universe on the other side of a black hole.