Hell in a Cell is an annual gimmick pay-per-view (PPV) and WWE Network event produced by WWE since 2009, generally held in October. The concept of the show comes from WWE's established Hell in a Cell match, in which competitors fight inside a 20-foot-high roofed cell structure surrounding the ring and ringside area. The main event match of the card is contested under the Hell in a Cell stipulation. The 2021 event was moved from the October slot to June, which was only the second time for the event to not be held in October; the first time was the September 2018 event. The 2021 event was the 13th event under the Hell in a Cell chronology. It was held on June 20, 2021—the previously scheduled date for Money in the Bank, which was moved to July 18—and featured wrestlers from the Raw and SmackDown brands.