Bad is the seventh studio album by the American singer-songwriter Michael Jackson. It was released on August 31, 1987, by Epic Records. Written and recorded between 1985 and 1987, Bad was Jackson's third and final collaboration with the producer Quincy Jones. Primarily featuring pop, dance, and R&B, as well as elements of funk, soul, jazz, rock, and hard rock, Bad incorporated new recording technology, including digital synthesizers. Jackson co-produced and composed all but two tracks, as the lyrical themes include self-improvement, romance, world peace, media bias, paranoia, and racial profiling. The album features appearances from Siedah Garrett and Stevie Wonder.

Prior to the release of Bad, Jackson reinvented his image to a more streetwise, mature persona and adopted a more aggressive sound, departing from his signature groove-based style and falsetto. Nine singles were released to promote the album, including the record-breaking five US number ones, "I Just Can't Stop Loving You", "Bad", "The Way You Make Me Feel", "Man in the Mirror" and "Dirty Diana", and the top-10 hit "Smooth Criminal". The film Moonwalker (1988), which included the music videos for several Bad songs, was used to promote the album. Jackson also embarked on his first solo world tour, performing 123 concerts across 15 countries for his Bad tour, attracting 4.4 million people as the tour grossed $125 million (equivalent to $322 million in 2023), making it the highest-grossing concert tour ever at the time.

Released nearly five years after Jackson's previous album, Thriller (1982), anticipation for Bad was high. The album sold more than 2.25 million copies in its first week in the US as it reached number one on the Billboard Top Pop Albums chart, and went on to be certified 11× platinum. It also reached number one in 24 other countries and was the best-selling album globally of both 1987 and 1988, being an enormous commercial success around the world. Bad received highly positive reviews, particularly for Jackson's vocals and the rich, more polished production. It has since been acclaimed as a staple of 1980s popular music, solidifying Jackson's status as a global superstar and being an extension of his influence on contemporary music.

Bad is one of the best-selling albums of all time having sold over 35 million copies worldwide. Numerous publications have ranked it in lists of the greatest albums of all time; some critics have noted aspects of the album, particularly the songwriting and pop sentiments, as being the best of Jackson's career. The album was nominated for six Grammy Awards, including Album of the Year. It won Best Engineered Recording – Non Classical and Best Music Video (for "Leave Me Alone"). "Bad" won an American Music Award for Favorite Soul/R&B Song. Jackson also received several special awards in recognition of the album's success. In 2012, an expanded reissue album, Bad 25, and a documentary film also titled Bad 25 were released to celebrate the album's 25th anniversary.