Mario & Sonic at the London 2012 Olympic Games is a 2011   and  developed by . It was published by  in Japan and Korea and by  elsewhere. As the third instalment in the  series, it was released on the  on 15 November 2011 in North America, 18 November 2011 in Europe, and 26 December 2011 in Japan. It was also released for the  in February 2012. Mario & Sonic is the official video game of the  and is licensed by the  through exclusive licensee International Sports Multimedia. The game is the only Wii title to come in a yellow  instead of a standard white case.

The game on the Wii and 3DS comprises a collection of numerous events based on the Olympic Games. Players assume the role of a  or  character while competing against the others in Olympic events. Mario & Sonic received mostly mixed reviews from critics upon release, with many criticising its gameplay as underwhelming. It proved to be commercially successful and was followed by a fourth game in the series, , which was released in November 2013 for the .

Mario & Sonic at the London 2012 Olympic Games comprises a collection of numerous events based on the modern . The game brings together the two titular characters and 18 more from both franchises to participate in environments based on the  of the  in . Each character has unique attributes which can serve as an advantage or disadvantage depending on the event. As with the game's predecessor, all player-characters are divided into four categories: all-around, speed, power, and skill.

The Wii version features a total of 30 Olympic events, including , , , , and . Re-imagined versions of previously existing events such as , , and  also appear. The game introduces new cooperative mechanics including "Dream Events", alternate versions of Olympic events that take place in locations from previous games of the Mario and Sonic series, and a challenge mode, which enables players to repeat complete challenges in various events. "London Party" mode takes place on a board game-like depiction of London in which four players may compete in various sporting events and minigames. The ultimate objective is to collect enough stickers to fill up a "tourist book" – the player who completes the book first wins