IK or Ik may mean:

  • IK Investment Partners, a European private equity firm
  • Inupiaq language (ISO 639 alpha-2), a group of dialects of the Inuit language, spoken in northern and northwestern Alaska.
  • Ik people of Uganda, made famous by anthropologist Coin Turnbull's book The Mountain People
    • The Ik language
  • Ik River in Russia
  • IK code, a classification of resistance to mechanical impacts
  • an abbreviation for Inverse kinematics, a branch of mechanics
  • an acronym for Index Kewensis, a publication maintained by the Royal Botanic Gardens, Kew
  • an abbreviation for Iparretarrak, the Basque nationalist organization
  • the IATA airline designator of Imair Airlines
  • the regional code for Ilm-Kreis in Germany
  • an abbreviation for the German term Internationale Kerze (international candle), an old photometric unit to measure luminous intensity
  • a Dutch word for "I" (the first-person singular personal pronoun in the subject case)
  • an abbreviation for the computer game International Karate
  • an acronym for "I know", used in instant messaging and chat rooms
  • Indigenous knowledge, another name for traditional knowledge such as that held by indigenous peoples