Kick-Ass is a 2010 superhero/action-comedy film based on the comic book of the same name by Mark Millar and John Romita, Jr. The film was directed by Matthew Vaughn, who co-produced the film with actor Brad Pitt, and co-wrote the screenplay with Jane Goldman. The film's general release was on 26 March 2010 in the United Kingdom and on 16 April 2010 in the United States.

The film tells the story of an ordinary teenager, Dave, who sets out to become a real-life superhero, calling himself "Kick-Ass". Dave gets caught up in a bigger fight when he meets Big Daddy, a former cop who, in his quest to bring down the drug lord Frank D'Amico, has trained his 11-year-old daughter to be the ruthless vigilante Hit-Girl.

Despite having generated some controversy for its profanity and violence performed by a child actor, Kick-Ass has received mostly positive reviews.

Dave Lizewski (Aaron Johnson), an ordinary teenager, becomes a real-life superhero in New York City, despite having no superpowers. After his first crime-fighting encounter leaves him with permanent nerve damage, he gains an enhanced capacity to endure pain, and surgical implants required to repair multiple skeletal fractures give him resistance to further bone-crushing injuries. His effort to conceal the truth, claiming he had had his clothes thrown off after being mugged, leads to rumors that he is gay. His longtime crush, Katie Deauxma (Lyndsy Fonseca) immediately attempts to become his friend, having always wanted a "gay BFF." Dave hesitantly goes along with it. After intervening in a gang attack, Dave's actions are recorded by a bystander and put on the internet. Calling himself "Kick-Ass," he sets up a MySpace account so he can be contacted for help. After responding to a request from Katie, he goes to deal with a drug dealer, Rasul, who has been harassing her. Rasul and his thugs quickly overpower him, but he is rescued by 11-year old vigilante Hit-Girl (Chloë Moretz), who kills his attackers and then leaves with her father, Big Daddy (Nicolas Cage). They believe he has potential, but warn him to be more careful, and give him a way to contact them if needed.

Big Daddy is Damon Macready, a former cop who has a long-standing grudge with crime boss Frank D'Amico (Mark Strong) for framing him as a drug dealer, leading to the suicide of his wife. His former partner at the New York Police Department, Marcus Williams, became guardian to his daughter, Mindy. Big Daddy, however, has reclaimed Mindy and is training her to be a skilled crime-fighter, against Marcus' wishes, hoping to take down D'Amico, starting by sabotaging his organisation. D'Amico, however, is led to believe that it is Kick-Ass who is responsible for Big Daddy's actions, and embarks on a campaign to eliminate him. His son, Chris (Christopher Mintz-Plasse), suggests a different approach. He assumes the role of vigilante "Red Mist," in order to befriend Kick-Ass and lure him into a trap. But the trap is undone by Big Daddy, who independently kills D'Amico's men and sets the building on fire. Following his escape from the warehouse fire, Dave determines to quit being Kick-Ass. He confesses the truth to Katie, and she forgives him and becomes his girlfriend. A week later, Dave finds a series of urgent messages from Red Mist, requesting they meet. Saying he must do one more thing as Kick-Ass, he meets Red Mist, who is actually using him as a ruse to lead the D'Amico thugs to Big Daddy. Upon arriving at an intended meeting place, D'Amico's men storm the place and capture Big Daddy, taking Kick-Ass with them. . D'Amico intends to have his thugs torture and execute his captives in a live Internet broadcast viewed by millions, including Katie and Marcus, who are both powerless to intervene. Hit-Girl, who survived the shooting, arrives and kills all the gangsters; during the struggle one thug sets Big Daddy on fire. He and Hit-Girl say a tearful farewell before he succumbs to his injuries. Kick-Ass tries to convince Hit-Girl to quit her dangerous lifestyle, but she plans to finish what her father started, and Kick-Ass reluctantly agrees to help.

In the assault on D'Amico's headquarters, Hit-Girl kills most of the henchmen but runs out of ammunition and is pinned in the penthouse kitchen under fire. Kick-Ass arrives in the nick of time on a jet pack fitted with gatling guns, and kills the remaining thugs. Kick-Ass and Hit-Girl then take on D'Amico and his son. Kick-Ass fights Red Mist but they manage to knock each other out. Hit-Girl fights D'Amico, but she is eventually overpowered. As D'Amico is about to finish off Hit-Girl, Kick-Ass comes to the rescue armed with the rocket launcher, blasting D'Amico out of the window where he explodes in mid-air. Red Mist revives in time to see Kick-Ass and Hit-Girl leaving on the jet pack, and is powerless to stop them. Mindy and Dave retire from crime fighting to live a more normal life. Mindy returns to live with Marcus, and enrolls at Dave's school. Dave explains that although he is done with crime fighting, a new "generation" of superheroes have been inspired by his endeavor, and the city is safer as a result. Red Mist is shown donning a new mask as he quotes Jack Nicholson as the Joker, "As a great man once said, 'Wait till they get a load of me'."