| Abbreviation | Definition |
|---|---|
| IOO | Institute of Ophthalmology |
| IOP | Institute of |
| IOP | Institute of Packaging |
| IOPB | Institute of Physics Bhubaneswar |
| IOPI | Institute of Physics in Ireland |
| IOPL | Institute Of Political Leadership |
| IOPP | Institute of Packaging |
| IOPP | Institute of Packaging Professionals |
| IOPP | Institute of Packaging Professionals's |
| IOPS | Institute Of Physics in Scotland |
| IOQ | Institute of Quarrying |
| IOQ | Institutes of Quality |
| IOR | Institute of Operational Risk |
| IOR | Institute of Operations Research |
| IOR | Institute of Recruiters |
| IOR | Institute of Refrigeration |
| IOR | Institute of Roofing |
| IORB | Institute for Outlier Research in Business |
| IOS | Institute of Swimming |
| IOSH | Institute Of Occupational Safety And Health |