When may refer to:

• When?, one of the Five Ws, questions used in journalism
• WHEN, the former call letters of TV station WTVH in Syracuse, New York, U.S.
  • WHEN (AM), a sports radio station in Syracuse once affiliated with WTVH

In music:

• When (band), a musical project of Norwegian artist Lars Pedersen
• When (album), an album by Vincent Gallo
• "When" (Shania Twain song)
• "When" (Eurovision song), the Irish entry in the Eurovision Song Contest 1976, performed by Red Vincent Hurley
• "When" (1958 song), a song popularized by The Kalin Twins
• "When" (1980 song), a song recorded by Perry Como
• "When", a song by Megadeth from The World Needs a Hero
• "When", a song by Opeth from My Arms, Your Hearse
• When! Records, a UK record label whose artists include Overseer