WrestleMania is a professional wrestling live event held annually between mid-March and mid-April by WWE, the world's largest professional wrestling promotion. Since premiering in 1985, 36 editions followed, most recently in Tampa, Florida on April 10 and 11, 2021. It is the most successful and longest-running professional wrestling event in history. The event is shown through pay-per-view (PPV), and has also been available to stream through the WWE Network since 2014 and Peacock since 2021. WrestleMania was conceptualized by WWE chairman Vince McMahon and named by ring announcer and WWE Hall of Famer Howard Finkel. It is the company's flagship event and along with Royal Rumble, SummerSlam, Survivor Series, and Money in the Bank, it is referred to as one of the "Big Five", WWE's five biggest annual events of the year.

The widespread success of WrestleMania helped transform professional wrestling. The annual event has facilitated the rise to stardom of several top WWE wrestlers. Celebrities such as Aretha Franklin, Cyndi Lauper, Muhammad Ali, Mr. T, Alice Cooper, Lawrence Taylor, Pamela Anderson, Mike Tyson, Donald Trump, Floyd Mayweather Jr., Pete Rose, Burt Reynolds, Donnie Wahlberg, Mickey Rourke, Snoop Dogg, Sean "Diddy" Combs, Kid Rock, Fred Durst, Ozzy Osbourne, Ronda Rousey, Rob Gronkowski, Shaquille O'Neal, and Bad Bunny have participated or made special appearances within the events. Rousey herself later became a WWE wrestler and was one of the three women to compete in the very first women's match to headline a WrestleMania at WrestleMania 35 in 2019.

The first WrestleMania was held in Madison Square Garden in New York City; the 10th and 20th editions were also held there. WrestleMania III in the Detroit suburb of Pontiac, Michigan was the highest-attended indoor sports event in the world, with 93,173 fans in attendance. The record stood until February 14, 2010, when the 2010 NBA All-Star Game broke the indoor sporting event record with an attendance of 108,713 at Cowboys Stadium, since renamed AT&T Stadium, in Arlington, Texas. In 2016, WrestleMania 32 surpassed WrestleMania III as the highest-attended professional wrestling event ever held in America, with 101,763 fans in attendance at AT&T Stadium, although the company revealed that attendance figures are manipulated for marketing purposes through investor calls. All editions of the event have been hosted in North American cities, with 35 in the United States and two in Canada.

The only WrestleMania in the event's history to not air live and be held without fans in attendance was WrestleMania 36 in 2020 due to the COVID-19 pandemic; it was the first major professional wrestling event to be affected by the pandemic. It was also the first to be held across two nights, with each WrestleMania since becoming two-night events. WrestleMania 37 in 2021 was the company's first event to have fans in attendance during the pandemic, although at a reduced venue capacity, before the company resumed live touring in July that year with full capacity crowds.