Extreme Championship Wrestling (ECW) was an American professional wrestling promotion that was based in Philadelphia, Pennsylvania, and operated by its parent company HHG Corporation. The promotion was founded in 1992 by Tod Gordon as National Wrestling Alliance (NWA) affiliate Eastern Championship Wrestling. The following year, businessman and wrestling manager Paul Heyman took over the creative end of the promotion from Eddie Gilbert. Under Heyman, the promotion was rechristened as Extreme Championship Wrestling.

The promotion was known for highlighting a "hardcore wrestling" style, with matches regularly featuring weapons (including the frequent use of chairs, tables, and fire) and revolving around adult-themed storylines. Though the hardcore style was the main focus, ECW also showcased various international styles of professional wrestling not usually seen in the U.S., ranging from Mexican lucha libre to Japanese puroresu. Heyman's creative direction created new stars, and established ECW as the third major national wrestling promotion in the United States in the second half of the 1990s, competing with the World Wrestling Federation (WWF, now WWE) and World Championship Wrestling (WCW). The promotion debuted on national television in 1999 with the weekly show ECW on TNN.

ECW held its final events in January 2001, shortly before its parent company folded when it was unable to secure a new national TV contract. The World Wrestling Entertainment, Inc. (WWE) purchased the assets of the company from bankruptcy in January 2003. Following the success of the One Night Stand tribute show in 2005, WWE relaunched the ECW franchise as a third brand in 2006 alongside their existing Raw and SmackDown brands, producing ECW on Sci-Fi for close to four years until it aired its final episode in 2010, on the rebranded Syfy.

Following the lead of the World Wrestling Federation, the majority of American professional wrestling promotions in the 1980s and early 1990s orientated their style and presentation towards catering to mainstream audiences, families and casual fans. However, under the creative direction of Paul Heyman, ECW rebranded itself as "Extreme Championship Wrestling" in 1994 and orientated its entire style and presentation towards a gritty, counter-cultural, underground-style presentation directly inspired by the emerging cultural forces of grunge music, hip-hop and extreme sports. In contrast to clean-cut wrestling shows centred around "superhero" archetypes, ECW pioneered the use of adult-orientated shows featuring high levels of violence, vulgarity, and sexuality centred around anti-hero characters to develop a niche separate to that of its peers. ECW further accentuated the ruckus atmosphere of its shows through the use of contemporary chart music instead of using stock music; the performers in ECW would make their entrances accompanied by the music of artists such as Metallica, Alice in Chains, Pearl Jam, Dr. Dre and Ice Cube.

Although the concept of "hardcore wrestling" (a style of professional wrestling associated with the use of objects as weapons) did not originate with ECW, they were widely credited with popularizing the style in the United States and were intimately associated with it. Although hardcore wrestling became the calling card of the promotion, ECW has also been credited with helping to introduce other professional wrestling styles such as lucha libre and puroresu to the American audience.

Based in the working-class city of Philadelphia, ECW had its origins in 1989 under the banner Tri-State Wrestling Alliance (TWA) owned by Joel Goodhart. In 1992, Goodhart sold his share of the company to his partner, Tod Gordon, who created his own promotion from TWA's remnants, Eastern Championship Wrestling (ECW). When Eastern Championship Wrestling was founded, it was not a member of the National Wrestling Alliance (NWA), though it joined the alliance on September 3 1993 at the behest of its lead booker "Hot Stuff" Eddie Gilbert. Gilbert, through his position as lead booker of ECW, managed to secure television time on SportsChannel Philadelphia starting in April 1993. Gilbert, after a falling out with Tod Gordon, was replaced in September 1993 by then-28-year-old businessman Paul Heyman. Heyman, known in professional wrestling as Paul E. Dangerously, had just been fired by World Championship Wrestling (WCW) and was looking for a new challenge.

Heyman's creative influence had an immediate impact on ECW, and throughout 1993 and into 1994 the terms "Hardcore" and "Extreme" were increasingly used to characterize both the in-ring style and the general presentation of the promotion. Instead of relying on former WWF stars such as Jimmy Snuka, Heyman pivoted the promotion to centering around local up-and-coming talents such as Shane Douglas, Sabu, The Sandman and Tommy Dreamer.

By 1994 ECW was proving to be the strongest member of what remained of the National Wrestling Alliance. It was therefore decided by consensus between ECW and the rest of the NWA that ECW's main star, Shane Douglas, would win a tournament to win the vacant NWA Worlds Heavyweight Championship. However, unbeknownst to the NWA, ECW operators Tod Gordon and Paul Heyman secretly planned to use the occasion to publicly break from the NWA and relaunch ECW as its own standalone entity. Gordon and Heyman had lost faith in the NWA to provide any value to them as wrestling promoters. Additionally, instead of offering cooperation and mutual support, other member promotions of the NWA were undermining ECW's business with underhanded tactics, something Gordon and Heyman wanted revenge for.