[3][4][5] It is a non-profit organisation open to people who score at the 98th percentile or higher on a standardised, supervised IQ or other approved intelligence test.

[2] Australian Roland Berrill and Lancelot Ware, a British scientist and lawyer, founded Mensa at Lincoln College, in Oxford, England in 1946, with the intention of forming a society for the most intelligent, with the only qualification being a high IQ.

[9] The society was ostensibly to be non-political in its aims and free from all other social distinctions, such as race and religion.

For example, American Mensa has 134 local groups, with the largest having over 2,000 members and the smallest having fewer than 100.

There are also electronic SIGs (eSIGs), which operate primarily as email lists, where members may or may not meet each other in person.

It is held in a different city every year, with speakers, dances, leadership workshops, children's events, games, and other activities.

[26][27] In Europe, since 2008 international meetings have been held under the name EMAG (European Mensa Annual Gathering), starting in Cologne that year.

[28] The next meetings were in Utrecht (2009), Prague (2010), Paris (2011), Stockholm (2012), Bratislava (2013), Zürich (2014), Berlin (2015), Kraków (2016), Barcelona (2017), Belgrade (2018) and Ghent (2019).

This has included Gold Coast, Australia (2017),[31] Cebu, Philippines (2018),[30] New Zealand (2019), and South Korea (2020).

[45][47][48] In 2018, Mehul Garg became the youngest person in a decade to score the maximum of 162 on the Mensa IQ test.