Super Mario Bros. (スーパーマリオブラザーズ, Sūpā Mario Burazāzu, sometimes referred to as Mario, Super Mario or SMB) is a video game released by Nintendo in late 1985 for the Nintendo Entertainment System. It made a huge impact on home entertainment when it was released, and is now considered the classic of the medium. Super Mario Bros. featured bright, expansive worlds that changed the way video games were created. Although often wrongly credited as the first scrolling platform game (there are at least a half dozen earlier), it is the first console original in this genre to feature smooth-scrolling levels, which made it a landmark in home video-gaming, and it is considered by a number of critics as one of the best games ever.

Super Mario Bros. is listed in The Guinness Book of World Records as the best-selling video game of all time, and was largely responsible for the initial success of the Nintendo Entertainment System, as well as ending the two year slump of video game sales in the United States after the video game crash of 1983. It has inspired countless imitators and was one of Shigeru Miyamoto's most influential early successes. The game starred the Italian plumber Mario and his brother Luigi. Mario went on to become Nintendo's most well known mascot. The theme music, by Koji Kondo, is recognized worldwide, even by those who have not played the game.

The game was succeeded by a direct sequel in Japan (later retitled Super Mario Bros.: The Lost Levels outside Japan), and by Super Mario Bros. 2, a slight revision of Yume Kōjō: Doki Doki Panic with playable Mario characters, elsewhere in the world. There is also another sequel called Super Mario Bros. Special released around the same time as the original sequel, but is was released only in Japan by Hudson Soft, so it was relatively obscure.