| OII | Oceaneering International Inc
| Others |
| OII | Office of Identity and Inclusion
| Others |
| OII | Office of Immunology and Inflammation
| Others |
| OII | Office of Innovation and Improvement
| Others |
| OII | Office of Institutional Information
| Others |
| OII | Office of Institutional Integrity
| Others |
| OII | Office of Instructional Innovation
| Others |
| OII | Office of International Initiatives
| Others |
| OII | Office of Investment and Innovation
| Others |
| OII | Ohio Insurance Institute
| Others |
| OII | Ohio's Insurance Industry
| Others |
| OII | Online Innovation Institute
| Others |
| OII | Online Internet Institute
| Others |
| OII | Operating Industries Inc
| Others |
| OII | Operations Intelligence Interface
| Others |
| OII | Ophthalmic Innovations International
| Others |
| OII | Order Instituting Investigation
| Others |
| OII | Organisation Intersex International
| Others |
| OII | Organization Intersex International
| Others |
| OII | Other Insurance Information
| Others |
| OII | Out Island Interiors
| Others |
| OII | Out Island Internet
| Others |
| OII | Oversteer In Ink
| Others |
| OII | Oxford Internet Institute
| Others |