The 2008 SummerSlam was the 21st annual SummerSlam professional wrestling pay-per-view (PPV) event produced by World Wrestling Entertainment (WWE). It was held for wrestlers from the promotion's Raw, SmackDown, and ECW brand divisions. The event took place on August 17, 2008, at Conseco Fieldhouse in Indianapolis, Indiana. It was the first PPV of the PG Era, although nobody noticed it at the time because there were still two Ruthless Aggression rivalries still going on, one of which ended at this event. The transition into the PG Era was more noticeable on the next episode of Monday Night Raw. It was also the first SummerSlam PPV broadcast in high definition. It would be the last Summerslam to take place in a location other than Los Angeles or New York until 2019.

Gainbridge Fieldhouse is an indoor arena located in downtown Indianapolis, Indiana, United States. It opened in November 1999 to replace Market Square Arena. The arena is the home of the Indiana Pacers of the National Basketball Association and the Indiana Fever of the Women's National Basketball Association. The fieldhouse also hosts college basketball games, indoor concerts, and ice hockey.