Jackass is an American reality slapstick comedy television series and media franchise created by Jeff Tremaine, Spike Jonze, and Johnny Knoxville. It originally aired as a TV series of three short seasons on MTV between October 2000 and August 2001, with reruns extending into 2002. The series featured a compilation of pain and embarrassment inducing stunt performances and pranks on each other and the public, with the regular cast entailing Johnny Knoxville, Bam Margera, Chris Pontius, Ryan Dunn, Steve-O, Dave England, Ehren McGhehey, Jason "Wee Man" Acuña, and Preston Lacy.

After MTV ended Jackass broadcasts in 2002, it grew into a media franchise, which includes the spin-offs Wildboyz and Viva La Bam; five feature films released by Paramount Pictures, four of which with expanded compilation films; a video game and a mobile game; boxed DVD sets of unreleased footage of the original TV show, a short-lived website featuring blogs and videos, merchandise, and several other videos released by various other means.

The Jackass series was controversial due to its perceived indecency and potential encouragement of dangerous behavior. The show placed 68th on Entertainment Weekly's "New TV Classics" list, and is a significant part in 2000s American popular culture.

In the late 1990s, aspiring actor and writer Johnny Knoxville had moved from Knoxville, Tennessee to Los Angeles, California, and landed work in commercials in order to support his wife and infant daughter. Among his ideas was to produce an article that involved testing various self-defense equipment on himself as a homage to his hero, gonzo journalist Hunter S. Thompson. Knoxville pitched the story to several magazines but all refused to cover the story due to liability concerns. However, in 1996, Knoxville was contacted by Big Brother, a skateboarding magazine for which Jeff Tremaine was an editor, and convinced Knoxville to do the stunt and film it. The stunt featured Knoxville testing out pepper spray, a stun gun, a taser, and a .38 caliber gun with a bulletproof vest, with the gun stunt only being included in the Big Brother video entitled Number Two, which also featured an appearance by future Jackass cast member Jason "Wee Man" Acuña. Other contributors to Big Brother at this time were Chris Pontius and Dave England, who went on to become a part of the Jackass cast; Dimitry Elyashkevich, who became the show's cinematographer; Rick Kosick, who became a cameraman; Sean Cliver, who became the show's main photographer; and Loomis Fall, who made recurring appearances throughout the Jackass TV show and films.

Around this time, up-and-coming professional skateboarder Bam Margera was filming his family and friends from his hometown of West Chester, Pennsylvania. Collectively known as the CKY crew (short for "Camp Kill Yourself"), these home videos were ultimately compiled and released as part of the CKY video series. The videos featured stunts, pranks, and skateboarding with a cast that primarily included Bam, Ryan Dunn, Brandon DiCamillo, Raab Himself, Rake Yohn and Margera's family; his mother April, his father Phil, his uncle Don Vito, and his older brother and CKY drummer Jess. Like the Big Brother videos, the CKY releases quickly became a cult hit and attracted the attention of Tremaine, who saw the second CKY video, CKY2K, and flew Margera to Los Angeles to meet with him.

The video convinced Tremaine that the CKY group would fit perfectly with the idea of a stunt and prank television show that he, Knoxville, and Spike Jonze had been planning. After demo footage had been shot and pitched to several networks, Saturday Night Live made an offer to have the crew be a recurring segment on the show. The offer was rejected, and a subsequent bidding war between Comedy Central, FX, and MTV resulted in the three accepting a deal from the latter for a half-hour weekly show and greater creative control. Knoxville, Tremaine, and Jonze are credited as executive producers. Van Toffler, president of MTV, said: "We just knew there were a bunch of knuckleheads out there who had a very high tolerance for stupidity and pain."

Soon after the MTV deal, Tremaine got in touch with periodic contributor to Big Brother Steve-O, who was working as a clown at a local Florida flea market, and had him film videos of his stunts for the television show, but none of the stunts were cleared by MTV management. Some time later, Dave England suggested and brought in his friend Ehren McGhehey, a fellow Oregon resident and extreme stunt participant. Preston Lacy would be the last of the original cast to join, after he and Knoxville previously worked together with Knoxville's ex-wife's clothing line. Knoxville told Lacy that he was making a new TV show and asked him if he could potentially write some ideas. Knoxville then convinced Lacy to perform the stunts himself.

After the establishment of Dickhouse Productions; a former Viacom company (now owned by Paramount Global) by Jeff Tremaine, Johnny Knoxville and Spike Jonze, Jackass officially debuted on October 1, 2000 on MTV. After the airing of the second episode, MTV gained its highest Sunday ratings in its history, drawing 2.4 million viewers among 12 to 34-year-olds, its target demographic.