| IRO | Impact Resistant Outerwrap 
| Others |
| IRO | In Receipt Of
| Others |
| IRO | In Region Of
| Others |
| IRO | In Respect Of ....
| Others |
| IRO | In the Region of
| Others |
| IRO | Include Route Object
| Others |
| IRO | Independent Rental Owners
| Others |
| IRO | Independent Review Office
| Others |
| IRO | Independent Review Organization
| Others |
| IRO | Independent Review Organizations
| Others |
| IRO | Independent Reviewing Officer
| Others |
| IRO | Independnat Reviewing Officer
| Others |
| IRO | Information Resource Officer
| Others |
| IRO | Institute for Research in Ophtalmology
| Others |
| IRO | Institution of Railway Operators
| Others |
| IRO | Institutional Research Office
| Others |
| IRO | Intelligence Recon Operative
| Others |
| IRO | Intended Rehabilitation Objective
| Others |
| IRO | Inter-Religious Organization
| Others |
| IRO | Internal Redirection Overlay
| Others |
| IRO | Internal Redirection/Overlay
| Others |
| IRO | Internal Review Office
| Others |
| IRO | Internaltional Ragnarok Online
| Others |
| IRO | International Race Officer
| Others |
| IRO | International Ragnarok Online
| Others |
| IRO | International Raspberry Organization
| Others |
| IRO | International Refugee Organization
| Others |
| IRO | International Refugee Organization (WWII)
| Others |
| IRO | International Relations Office
| Others |
| IRO | International Relations Officer
| Others |
| IRO | International Relations Officers
| Others |
| IRO | International Relief Organization
| Others |
| IRO | International Robot Olympiad
| Others |
| IRO | Internationale Rettungshunde Organisation
| Others |
| IRO | Investor Relations Officer
| Others |
| IRO | Iron Rock Offroad
| Others |
| IRO | Iroquoian languages
| Others |
| IRO | Itial Responding Officer
| Others |