Mario Kart 8 is a 2014 kart racing game developed and published by Nintendo for the Wii U. It features the Mario Kart series' game mechanics, in which players drive go-karts using Mario franchise characters in various race formats. Items placed along the course may be used to hinder opponents or gain advantages in the race. Mario Kart 8 introduces anti-gravity driving on walls or ceilings, and allows players to bump into each other for a short boost. It features single-player and multiplayer gameplay, as well as online multiplayer. The game was a critical success. Critics praised its new additions and courses, as well as its graphics and soundtrack. However, they criticized its limited battle mode. Since its release on May 29, 2014, Mario Kart 8 has sold over 8 million units, and is the best-selling Wii U game. Post-release, Mario Kart 8 has received several software updates and downloadable content, including additional characters, courses, and vehicles.

On April 28, 2017, Nintendo released Mario Kart 8 Deluxe,  an expanded re-release of Mario Kart 8 for the Nintendo Switch. Deluxe features a revamped battle mode, including five sub-modes. After launch, Deluxe received several software updates, including the "Booster Course Pass", a downloadable season pass which features 48 additional courses split into six waves set to be released by the end of 2023. Since its release, Deluxe has sold over 48 million units, making it the best-selling Nintendo Switch game and one of the best-selling games of all time. Deluxe was critically acclaimed, with many reviewers calling it the best Mario Kart game or one of the best racing games, though some criticized the lack of new content.