OIS may mean:

  • Overnight indexed swap, a type of interest rate swap
  • Object Oriented Input System, a cross-platform input system
  • Optical IP Switching, a computer optical network architecture
  • Optical Image Stabilization, a technique to stabilize the image in digital cameras and camcorders in order to increase picture quality
  • Ocular ischemic syndrome, a medical condition which blocks arterial blood flow to the eye
  • Oxygen isotope stages of the Weichselian glaciation used in paleoclimatology
  • Objective Interface Systems, a communications software and hardware company
  • Oeiras International School, an international school in Oeiras (suburb of Lisbon), Portugal
  • Oxford International School, an international English-medium school in Dhaka, Bangladesh
  • Oulu International School, a small public not-for-profit international school in Oulu, Finland
  • Ops in Surgery, The St George's Surgical Society, a society at St George's University
  • Örgryte IS, a Swedish sports club based in Gothenburg
  • Office Information System, an operating system used by WANG computers.