Super Mario Bros. Wonder is a 2023 platform game developed and published by Nintendo for the Nintendo Switch. It is the first traditional side-scrolling Super Mario game since New Super Mario Bros. U (2012). The player controls Mario, Luigi, and their friends as they attempt to stop Bowser, who plots to take over a new land known as the Flower Kingdom after using the magical Wonder Flower to fuse himself with the kingdom's castle.

Development for Super Mario Bros. Wonder began in 2019, with director Shiro Mouri taking inspiration from the original Super Mario Bros. and producer Takashi Tezuka seeking to reinvent the 2D Mario experience and introduce a new location.

The game became the fastest-selling Super Mario game, selling 4.3 million units in its first two weeks and reaching 16.03 million units by March 31, 2025. It received critical acclaim and was nominated for several awards, including the Golden Joystick Award for Game of the Year, The Game Award for Game of the Year and the British Academy Games Award for Best Game. A Nintendo Switch 2 version, titled Super Mario Bros. Wonder: Nintendo Switch 2 Edition + Meetup in Bellabel Park, will release in Q2 2026.

Super Mario Bros. Wonder is a side-scrolling platform game. As one of twelve player characters—Mario, Luigi, Princess Peach, Princess Daisy, yellow and blue Toads, Toadette, Nabbit and four types of Yoshis—the player completes levels across the Flower Kingdom with assistance from its flower-like denizens. Similarly to previous Super Mario games, players guide their character to the end of a level while avoiding enemies, such as Goombas and Piranha Plants, and transporting through Warp Pipes. Each stage contains multiple collectible "Wonder Seeds".

New power-ups include a fruit that transforms the player into an elephant, a flower that allows the player to create bubbles that capture enemies, and a mushroom that gives the player a drill hat that allows them to burrow into the ground or ceiling to evade enemies or bypass obstacles.

Wonder introduces the Wonder Flower, which triggers bizarre effects such as pipes coming to life, hordes of enemies spawning, and character appearances and abilities changing. The effects end when a player collects a Wonder Seed or leaves the area of effect.

A new feature allows players to equip badges, which are unlocked throughout the game and give different advantages to the player. They are divided into three different categories: Action Badges, which grant the player character an additional ability; Boost Badges, which give the player character an additional passive ability; and Expert Badges, which grant the player character an advanced skill. Only one badge can be activated at a time per level. They are usually optional and can be shut off for higher difficulty.

The game supports local multiplayer for up to twelve players in a room with a limit of four players active in a level. It also has some online multiplayer functionality. When playing through a level while playing online, translucent versions of up to three other players playing through the same level may be present. When other online players are present nearby, defeated players become ghosts and are given a short window of time to revive themselves by flying toward another player or a standee placed by another player.