| Acronym | Definition |
|---|
| OIU➣Okinawa International University (Japan) |
| OIU➣Operator Interface Unit |
| OIU➣Ohio Investigative Unit (Ohio Department of Public Safety) |
| OIU➣Office Interface Unit |
| OIU➣Optical Interface Unit |
| OIU➣Osaka Imperial University (now Osaka University; Japan) |
| OIU➣Optical Internal Urethrotomy |
| OIU➣Orbiter Interface Unit |
| OIU➣Omdurman Islamic University (Sudan) |
| OIU➣Old Ignatians' Union (Lane Cove, NSW, Australia) |