New Super Mario Bros. Wii​(New スーパーマリオブラザーズ Wii Nyū Sūpā Mario Burazāzu Wī?) is a side-scrolling platform video gamepublished and developed by Nintendo for the Wii video game console. The game was released on November 12, 2009 in Australia, November 15, 2009 in North America, November 20, 2009 in Europe and December 3, 2009 in Japan. It is the first game in the Mario main series since the Mario Bros. arcade game to feature simultaneous multiplayer gameplay, and the first title to include Nintendo's new 'Super Guide' feature. To highlight the uniqueness of the title, Nintendo chose to use a red case instead of the traditional white.

The game’s plot is similar to those of other side-scrolling Mario games. New Super Mario Bros. Wii follows Mario as he fights his way through Bowser’s henchmen to rescue Princess Peach. Mario has access to several power-ups that help him complete his quest, including the Ice Flower, the Fire Flower, and the Starman, each giving him unique abilities. While traveling through up to nine worlds with a total of 88 levels, Mario must defeat Bowser's children, the Koopalings and Bowser Jr., and Bowser himself before finally saving Princess Peach.

New Super Mario Bros. Wii has been critically and commercially successful with gaming aggregators GameRankings and Metacriticreporting average scores of 88% and 87/100, respectively. As of April 2011, it is the sixth best-selling game on the Wii, at 21.94 million copies sold worldwide.[6] It received several honors, including the 2009 Best Wii Game award from the 2009 Spike Video Game Awards,IGN, and GameTrailers.

Another New Super Mario Bros. game, New Super Mario Bros. Mii, is currently in development for the upcoming Wii U