are ogres or demons in Japanese folklore.

Oni may also refer to:

  • Oni (band), a Canadian progressive metal band
  • Oni Press, an independent comic book publisher
  • Ooni, the kings of Nigeria's Yoruba people
  • Oni–Adil, Indian composer duo
  • Miye Oni (born 1997), American basketball player
  • Oni Gozen, a Japanese female warrior from the 16th century
  • Oni, Maharashtra, a small village in Western India
  • Oni, Georgia, a town in Georgia
  • Oni (letter), the 16th letter of the three Georgian scripts
  • Oni: Thunder God's Tale, stop-motion series
  • Oni (video game), a 2001 third-person action video game made by Bungie
  • Adesuwa Oni (born 1989), British actress
  • Onimusha, a series of action video games made by Capcom
  • Oni Aliens, foes in the Gantz manga
  • Oni, the title of an unfinished Akira Kurosawa script that was later adapted to a video game named Nioh
  • Oni, a race of aliens from the manga and anime Urusei Yatsura
  • The Oni, a primary antagonist in seasons 8-10 of the TV series Ninjago
  • Oni (Street Fighter), an alternate form of Akuma that appears in the Super Street Fighter IV: Arcade Edition video game
  • Oni, an antagonist in the Mortal Kombat: Shaolin Monks video game
  • My Oni Girl, a 2024 anime film by Studio Colorido

ONI may refer to:

  • Office of Naval Intelligence, the United States Navy's intelligence agency
  • Office of National Intelligence, an Australian government intelligence agency
  • OpenNet Initiative, a project for tracking the use of Internet filtering and surveillance
  • ONI Systems Corporation, an optical networking company acquired by Ciena Corporation in 2002
  • ONI (Oxford Nanoimaging), a super-resolution microscope company
  • Oxygen Not Included, a simulation video game by Klei Entertainment
  • OASIS Neural Interface, a VR technology system used in Ready Player Two
  • Oceanic Niño Index, the numerical metric for El Niño used by the U. S government's NOAA