King Boo

is a Japanese media franchise created by Japanese game designer Shigeru Miyamoto for the video game company Nintendo. Starring Mario, the franchise began as a video game and has extended to other forms of media, including a television series, comic books, the films Super Mario Bros. (1993), The Super Mario Bros. Movie (2023), The Super Mario Galaxy Movie (2026), and the theme park area Super Nintendo World. Mario made his first video game appearance in the arcade game Donkey Kong (1981) and was featured in multiple Donkey Kong games prior to Mario Bros. (1983), the first game with "Mario" in the title. Mario video games have been developed by a variety of developers, with the vast majority produced and published by Nintendo and released on Nintendo's video game consoles.

The flagship Mario subseries is the Super Mario series of platform game starting with 1985's Super Mario Bros., which mostly follows Mario's adventures in the Mushroom Kingdom and typically relies on Mario's jumping ability to allow him to progress through levels. The franchise has spawned over 200 games of various genres and several subseries, including Mario Kart, Mario Party, Mario Tennis, Mario Golf, Mario vs. Donkey Kong, Paper Mario, and Mario & Luigi; several characters introduced in the Mario franchise, such as Luigi, Wario, and Yoshi, sparked successful franchises of their own.

The Mario series is one of gaming's most successful and renowned franchises, with many of its games, in particular within the Super Mario subseries, considered some of the greatest video games ever made. It is the best-selling video game franchise of all time, with more than 900 million copies of games sold, including more than 430 million for the Super Mario games alone, and one of the highest-grossing media franchises of all time. Mario is Nintendo's flagship franchise.

Media in the Mario franchise usually makes use of episodic instead of serialized plot lines, with the events of one entry bearing little impact on the others. Instead, narrative elements (such as a damsel in distress having to be rescued from a monstrous villain by the protagonist after an ambush or military incursion) are often reused as a backdrop to contextualize more specific scenarios; a measure intended to maximize the franchise's appeal to new audiences.