The 2018 SummerSlam was the 31st annual SummerSlam professional wrestling pay-per-view (PPV) and livestreaming event produced by WWE. It was held for wrestlers from the promotion's Raw, SmackDown, and 205 Live brand divisions. The event took place on August 19, 2018, at Barclays Center in Brooklyn, New York for the fourth and final consecutive year.

Thirteen matches were contested at the event, including three on the Kickoff pre-show. Nine matches, including two on the Kickoff pre-show, were championship matches. In the main event, Roman Reigns defeated Brock Lesnar to win Raw's Universal Championship, ending Lesnar's 504-day reign (although WWE officially recognizes it as 503 days). In the penultimate match, Ronda Rousey defeated Alexa Bliss to win the Raw Women's Championship, becoming the first woman to win a women's championship in both the Ultimate Fighting Championship and WWE. In other prominent matches, The Miz defeated Daniel Bryan, Samoa Joe defeated SmackDown's WWE Champion AJ Styles by disqualification (thus did not win the championship), and in the opening bout, Seth Rollins defeated Dolph Ziggler to regain Raw's Intercontinental Championship. The event was also the first SummerSlam not to feature John Cena since 2003.