The 2003 Backlash was the fifth Backlash professional wrestling pay-per-view (PPV) event produced by World Wrestling Entertainment (WWE). It was held for wrestlers from the promotion's Raw and SmackDown! brand divisions. The event took place on April 27, 2003, at the Worcester Centrum in Worcester, Massachusetts. It was the first Backlash event held under the WWE name after the promotion was renamed from World Wrestling Federation (WWF) to WWE in May 2002. The concept of the pay-per-view was based around the backlash from WrestleMania XIX.

The main event and featured match of the Raw brand was the encounter of Goldberg and The Rock, where Goldberg, in his first WWE pay-per-view, defeated The Rock by pinfall, following a spear and a Jackhammer. The featured match on the undercard was a WWE Championship match from the SmackDown! brand, between John Cena and the reigning champion, Brock Lesnar, where Lesnar defeated Cena by pinfall after an F-5. The other predominant match on the undercard was a six-man tag team match from the Raw brand, between the team of Triple H, Ric Flair, and Chris Jericho facing Shawn Michaels, Kevin Nash, and Booker T. Triple H, Flair, and Jericho won the match by pinfall, after Triple H hit Nash with a sledgehammer. The predominant undercard match from the SmackDown! brand was the encounter of the Big Show and Rey Mysterio, where Big Show pinned Mysterio after a chokeslam.

The event grossed $450,000 with 10,000 ticket sales and had a 0.67 buyrate. Following the event, Goldberg began a feud with Chris Jericho. At Bad Blood, Goldberg defeated Jericho via pinfall after a Jackhammer. Brock Lesnar began a storyline with Big Show over the WWE Championship. At Judgment Day, Lesnar defeated Big Show in a Stretcher match to retain the WWE Championship. Triple H engaged in a storyline with Kevin Nash over the World Heavyweight Championship. At Judgment Day, Nash defeated Triple H via disqualification; due to WWE regulations, Triple H retained the championship.