| Abbreviation | Definition |
|---|---|
| IOI | International Ocean Institute |
| IOI | International Ombudsman Institute |
| IOIS | Institute of Investigative Science |
| IOJ | Institute of Jainology |
| IOJ | Institute Onn Jaffar |
| IOK | Institute of Knowledge |
| IOL | Institute for |
| IOL | Institute for Open Leadership |
| IOL | Institute For Open Learning |
| IOL | Institute for Outdoor Learning |
| IOL | Institute of Linguists |
| IOL | Institute Of Living |
| IOLM | Institute of Our Lady of Mercy (UK) |
| IOM | Institute |
| IOMA | Institute of Management and Administration |
| IOMC | Institute of Medicine of Chicago |
| ION | Institute for Optimum Nutrition |
| ION | Institute of Navigat |
| ION | Institute Of Navigation |
| IONS | The Institute Of Noetic Sciences |