The Super Mario Bros. theme, officially known as the "Ground Theme"[a] or "Overworld Theme",[1][2] is a musical theme originally heard in the first stage of the 1985 Nintendo Entertainment System video game Super Mario Bros.. It was one of six themes composed for the game by Nintendo sound designer Koji Kondo, who found it to be the most difficult track to compose for it. The theme has a calypso rhythm and usually receives a corresponding orchestration in games whose sound synthesizers can imitate steel drums.

Since being included in Super Mario Bros., it went on to become the theme of the series and has been a fixture in most of its titles. It has been reused and remixed in other Nintendo-published games, including Tetris DS, Nintendogs: Chihuahua and Friends, WarioWare, Inc.: Mega Microgames!, and every entry in the Super Smash Bros. series.