Bad or BAD may refer to:

• Evil, the opposite of moral good
• Erroneous, inaccurate or incorrect
• Unhealthy, or counter to well-being
• Antagonist, the threat or obstacle of moral good

• BAD-2, a Soviet armored trolley car
• Bank account debits tax, an Australian tax
• Bcl-2-associated death promoter, a pro-apoptotic protein
• Team B.A.D., a professional wrestling tag team

• Andy Warhol's Bad, a 1977 film
• Bad, an unfinished film by Theo van Gogh

• B. A. D., the Taiwanese boy band, who formed in 1998
• Big Audio Dynamite, Mick Jones' post-Clash band, from London
• Royce da 5'9", the American rapper known as Bad, in the group Bad Meets Evil

• Bad (album), a 1987 album by Michael Jackson
• BAD, or Bigger and Deffer, the second album by LL Cool J, 1987

• "Bad" (U2 song), 1984
• "Bad" (Michael Jackson song), 1987
• "Bad", from the 2011 album Symphony Soldier by The Cab
• "Bad" (Wale song), 2013
• "Bad" (David Guetta and Showtek song), 2014
• "Bad!" (XXXTentacion song), 2018
• "Bad" (James Bay song), 2019
• "Bad", by Don Diablo, featuring Zak Abel, 2020
• "Bad", from the 2024 album P1X3L by Phoebus Ng

• Bad (tour), a Michael Jackson world tour

• "Bad" is the German word for "bath/spa" and so is found in many placenames in German-speaking Europe, e.g. Bad Kissingen
• Bad, Azerbaijan, a village in the Quba District
• Bad, a village in the Agra district of India
• Bad, Uttar Pradesh, a census town in India
• Bād, alternate name for Badrud, a city in Iran
• Bad River (disambiguation), various rivers

• Banstead railway station, Surrey, England (National Rail station code)
• Barksdale Air Force Base, Bossier City, Louisiana, US (IATA airport code BAD)

• Bad (economics), the opposite of a good
• Bad (cuneiform), a cuneiform sign
• Little Miss Bad, a character in the Little Miss series of books by Roger Hargreaves
• Banda languages, spoken in Central Africa (ISO 639-2 and -5 codes "bad")
• Bipolar affective disorder
• Turkish cold bulgur soup, also known as Bad (Bat) in Turkish

• BADD (disambiguation)
• List of people known as the Bad
• Bad 25, 2012 special 25th anniversary edition of the Michael Jackson album Bad
• Bad 25 (film), a 2012 documentary film about the Michael Jackson album
• All pages with titles beginning with Bad
• All pages with titles containing Bad