The AAA Mega Championship is a professional wrestling world heavyweight championship in the Mexican Asistencia Asesoría y Administración (AAA; Spanish for "Assistance, Assessment, and Administration") promotion. Known officially in Spanish as the Mega Campeonato AAA, it is sometimes referred to in the English-language press as the "AAA World Heavyweight Championship". The title is the top championship of the AAA promotion. The championship is generally contested in professional wrestling matches, in which participants execute scripted finishes rather than in direct competition.
The title was established in 2007 via a single elimination tournament billed as the "Torneo Campeón de Campeones", or Champion of Champions Tournament, which effectively unified the International Wrestling Council (IWC) World Heavyweight Championship, the Grand Prix Championship Wrestling (GPCW) SUPER-X Monster Championship, the Mexican National Heavyweight Championship, and the Universal Wrestling Association (UWA) World Light Heavyweight Championship. The tournament field included the four reigning champions of the aforementioned titles as well as the number one contender to each championship. El Mesías, who entered the tournament as the IWC World Heavyweight Champion, became the inaugural AAA Mega Champion upon defeating the UWA World Light Heavyweight Champion entrant Chessman in the final round.
El Texano Jr.'s first reign is the longest in history at 735 days. The shortest reigning champion was Electroshock, who held the title for 86 days. El Mesías has held the title the most, with four reigns. El Texano Jr. is the current champion in his second reign, after defeating El Mesías on March 23, 2016, to win the vacant title. In 2011, the then-AAA Mega Champion and Total Nonstop Action Wrestling (TNA) founder Jeff Jarrett appeared with a redesigned version of the title on TNA programming. While Jarrett appeared in TNA, the title was referred to as the Mexican Heavyweight Championship. TNA used the Mega Championship belt on their programming, but due to Spike TV not allowing TNA to refer to AAA by name, a silver hexagonal plate was used to cover the AAA faceplate. On April 21, 2013, the title was defended outside AAA for the first time at Puerto Rico's World Wrestling League (WWL). In March 2015, the AAA Mega Champion El Patrón Alberto defended the championship in Lucha Underground, made possible through AAA's joint ownership of Lucha Underground. Overall, there have been 13 reigns shared among 8 wrestlers, with two vacancies.