Bad is a concept in ethics used to describe undesirable circumstances or events. Bad may also be:
- Bad (economics), a concept in economics which is used to describe an object or situation that is harmful to the persons affected by it, in contrast to a good
- Bad (album), a 1987 Michael Jackson album
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- "Bad" (Michael Jackson song), a song from that album
- "Bad" (U2 song), a song by the rock band U2
- Andy Warhol's Bad, a 1977 film
- In Germany, the first part of the names of most spa towns, a cognate to the English "bath"
- Bcl-2-associated death promoter, a pro-apoptotic protein
- Bad, Uttar Pradesh, a census town in India
- Royce da 5'9", American rapper known as "Bad" in the group Bad Meets Evil
