Rocket Raccoon, commonly referred to simply as Rocket, is a fictional character in the Marvel Cinematic Universe (MCU) media franchise voiced by Bradley Cooper and based on the Marvel Comics character of the same name. Rocket was based on movements from Sean Gunn and an actual raccoon named Oreo. Rocket is a hot-tempered mercenary and weapons expert who, along with his companion Groot, joins the Guardians of the Galaxy. They then come into conflict with Ronan the Accuser and Ego. Following the Blip, Rocket remains on Earth as a member of the Avengers. Five years later, Rocket and the Avengers quantum time travel to alternate universes to find the Infinity Stones. Following their success, Rocket joins the battle against an alternate Thanos, and rejoins the Guardians after their victory; departing for space. Later, he and the Guardians make their base on Knowhere before coming into conflict with Rocket's creator, the High Evolutionary. Rocket then assumes leadership of the Guardians of the Galaxy.

Rocket made his first appearance in Guardians of the Galaxy (2014), and has become a central MCU character, appearing in six films as of 2024^[update], in two episodes of the I Am Groot series of animated shorts on Disney+, and in the TV special The Guardians of the Galaxy Holiday Special (2022).

Rocket, originally named Subject: 89P13, was abducted from North America on Earth by the High Evolutionary and taken aboard his ship into space. He is subjected to illegal genetic and cybernetic experiments and placed in another cage of three other genetically and cybernetically tested animals in Batch 89, an otter named Lylla, a walrus named Teefs, and a white rabbit named Floor that he becomes friends with. 89P13 names himself Rocket after wanting to make flying ships and explore the sky with his friends. Rocket shows extreme intelligence, finding the flaw in the High Evolutionary's design to accelerate animal evolution that made them violent. The High Evolutionary plans to harvest Rocket's brain for further research and kill the rest of Batch 89. Rocket escapes his cage and frees Lylla before the High Evolutionary shoots her. Rocket mauls the High Evolutionary's face off in response, and Teefs and Floor are killed during crossfire with the High Evolutionary's guards, after which Rocket escapes.

At some point in his travels after escaping, Rocket becomes friends and partners with Groot, a sentient anthropomorphic tree.

In 2014, Rocket and Groot travel to Xandar, where they try to capture Peter Quill for a bounty, interfering in a fight between Quill and Gamora over possession of the Power Stone that Quill had acquired. All four are captured by the Nova Corps and sent to the space prison, the Kyln. Rocket devises a plan to escape from the Kyln, and they escape along with Drax the Destroyer, another inmate. The five then travel to Knowhere to sell the Power Stone, where Rocket and Drax have a heated argument. After Drax drunkenly calls Ronan the Accuser to confront him, Ronan acquires the Power Stone. Rocket resists further involvement in the affair, but Groot persuades him to rescue Quill and Gamora from the Ravagers, and Quill then persuades all five of them to attempt to stop Ronan. As other members of the team battle Ronan aboard his ship, the Dark Aster, Rocket crashes a Ravager ship through the Dark Aster, which crash-lands on Xandar. Groot sacrifices himself to shield Rocket and the team, and the remaining Guardians are able to gain control of the Power Stone and destroy Ronan. Rocket plants a sapling cut from Groot in a pot, which grows into a baby of his species, whom Rocket adopts, also naming Groot in his biological father's honor.

Two months later, Rocket and the Guardians are hired by the Sovereign to fight off an alien attacking their valuable batteries, in exchange for Nebula. Annoyed by the arrogance of the Sovereign, Rocket steals some of their batteries, leading the Sovereign fleet to chase and attack the Guardians' ship. They crash land on a planet, where Quill meets his father, revealed to be Ego, a primordial Celestial who manifests a human avatar that allows him to interact with other races. Quill, Gamora, and Drax go with Ego to his planet while Rocket and Groot stay behind to watch Nebula and repair the ship. Ravagers arrive searching for Quill and, after a fight, capture Rocket and Groot and free Nebula. The Ravagers mutiny against their leader, Yondu, and aboard the Ravager ship, Rocket and Yondu plot their escape, eventually destroying most of the Ravager vessel except for a breakaway quarter, called the Quadrant, in which they travel to Ego. They learn that Ego is an evil living planet intent on dominating the universe. Quill keeps Ego occupied in combat with his newfound Celestial powers until Rocket is able to assemble a bomb, which the baby Groot places in Ego's brain. Later, Rocket and the rest of the Guardians hold a funeral for Yondu.

Sometime later, Rocket hears an explosion in the Quadrant and investigates, finding Groot. Rocket finds himself unable to stay mad when Groot gives Rocket an artistic drawing he made of the Guardians. Rocket is then almost sucked out of the ship before Groot saves him.

Four years later, Rocket and the Guardians respond to a distress signal and end up rescuing Thor, who is floating in space amidst the wreckage of the Statesman. Gamora tells them of the plan to obtain the Infinity Stones, and the Guardians split up, with Rocket and Groot accompanying Thor to Nidavellir to create a new weapon. On the way, Rocket gives Thor a replacement for an eye Thor has lost. They find an abandoned Nidavellir and meet the dwarf king Eitri. The four work together to create Stormbreaker, a powerful axe that also grants Thor the power of the Bifröst. Thor transports himself, Rocket, and Groot to Wakanda on Earth via the Bifröst to help members of the Avengers, Bucky Barnes, and the Wakandan army in the battle against the Outriders. During the battle, Rocket asks Barnes if he can have his arm, but after being declined, vows to get it. Later, Rocket watches helplessly as Groot weakly calls out "I am Groot" one final time as he disappears in the Blip. Director James Gunn revealed that this phrase translated to "...Dad?" as Groot looked to Rocket for help.