Super Mario Bros. is a platform video game developed and published by Nintendo that was released for the Family Computer and Nintendo Entertainment System in 1985. This game began the shift from single-screen gameplay to side-scrolling platformer levels. Despite not being the first game in the Mario franchise, it is the most iconic and introduced a variety of series staples such as power-ups, classic enemies and the usual task of the player having to rescue Princess Peach from King Koopa.

The creation of Super Mario Bros. kicked off an entire series of Super Mario platformer titles. Its success is what made the whole genre popular and helped the North American gaming industry revive after the 1983 video game crash. In addition, it was largely responsible for the initial success of the NES console, with which it was bundled a launch title. With over 40000000 copies sold worldwide, Super Mario Bros. remained the best selling title for near three decades, till it was surpassed by Wii Sports. A successor named Super Mario Bros. 2 in Japan (later renamed Super Mario Bros.: The Lost Levels in North America) was released on June 3, 1986. Another successor sharing its English name with its predecessor's Japanese name was released on October 9, 1988. A third successor named Super Mario Bros. 3 was released on October 23, 1988.

Super Mario Bros. has been ported to many consoles. It was one of the NES games that could be played on the Nintendo PlayChoice-10 and NES Classic Edition, and it was released on the Wii, Wii U, and Nintendo 3DS Virtual Console and on Nintendo Switch's Nintendo Entertainment System - Nintendo Switch Online.

There is a heavy dispute over the North American release date for the game, as different sources providing different dates with no room for verification. Despite this complication, Nintendo officially states the release as October 18, 1985.