"Bad" is a song by American recording artist Michael Jackson. It was released by Epic Records on September 7, 1987, as the second single from his seventh studio album Bad. The song was written and composed by Jackson, and produced by Quincy Jones and Jackson. Jackson stated that the song was influenced by a real-life story he had read about, of a young man who tried to escape poverty by attending private school but ended up being killed when he returned home.

"Bad" received positive reviews, with some critics noting that "Bad" helped give Jackson an edgier image. It reached number one on the Billboard Hot 100, and remained there for two weeks, becoming the album's second number-one single, and Jackson's eighth number one entry on the chart. It also charted on the Hot R&B Singles, Hot Dance Club Play and Rhythmic chart at number one. "Bad" is certified Platinum by the Recording Industry Association of America (RIAA). Internationally, the song was also commercially successful, charting at the top of the charts in Ireland, Norway, Spain and the Netherlands as well as charting in the top ten in Australia, Austria, Canada, France, West Germany, New Zealand, Switzerland, Sweden and the United Kingdom.

The short film for "Bad" premiered in a TV special, Michael Jackson: The Magic Returns, on CBS during prime time on August 31, 1987. It was directed by Martin Scorsese and co-starred Wesley Snipes in one of his first appearances. The video, inspired in part by the film West Side Story, shows Jackson and a group of gangsters portraying a street gang dancing in a subway station, set at the Hoyt–Schermerhorn Streets station. It has been praised by critics as one of the most iconic and greatest videos of all time; Jackson's outfit has been recognized as an influence on fashion.