Devil's Night is one name associated with October 30, the night before Halloween, particularly in the metropolitan Detroit, Michigan, area, though it is also "celebrated" in other areas in the United States like Camden, New Jersey. It is also known as Mischief night

Traditionally, kids and teens in the Metro Detroit area played pranks on their neighbors, which largely consisted of ringing doorbells and running away, soaping or waxing windows, throwing eggs at houses and cars, overturning garbage cans, and "decorating" trees with toilet paper.

Beginning in the 1970s the mischief became more destructive, particuarly in Detroit's inner-city neighborhoods, and extended into hundreds of acts of arson and vandalism. The destruction reached a peak in the mid- to late-1980s, with more than 800 fires set in 1984, and 500-800 fires in the three days and nights before Halloween in typical years.

In 1995, Detroit city officials organized and created Angel's Night on and around October 30. Each year, as many as 40,000 volunteers are gathered to patrol neighborhoods and prevent crime. Additionally youth curfews of as early as 6pm are instituted on the days preceding Halloween. This has resulted in a decline to 50-60 fires per day in the days around Halloween.

Devil's Night was chronicled in sociologist Ze'ev Chafets' 1991 book Devil's Night and Other True Tales of Detroit, and fictionalized in the 1994 movie The Crow. While the term is still well-known by Michigan residents, the news media in Detroit currently refer to the event as Angel's Night in an effort to boost the efforts of the volunteers.

The name Devil's Night or Mischief Night is used by various pranksters in the eastern U.S. and Canada, although the acts are far less destructive, criminal or violent.