| Acronym | Definition |
|---|
| IRO | In Receipt Of |
| IRO | International Relations Office |
| IRO | Independent Review Organization (insurance industry) |
| IRO | International Ragnarok Online (gaming) |
| IRO | In Respect Of |
| IRO | International Refugee Organization |
| IRO | Individuele Reintegratie Overeenkomst (Dutch: Individual Reintegration Agreement; unemployment benefits) |
| IRO | Inland Revenue Ordinance |
| IRO | Investor Relations Officer |
| IRO | Information Resource Officer (US Department of State) |
| IRO | Industrial Relations Ordinance (Pakistan) |
| IRO | Iron Rock Off Road, Inc (Shakopee, MN) |
| IRO | Internationale Rettungshunde Organisation (German: International Rescue Dog Organisation) |
| IRO | International Rescue Dog Organisation |
| IRO | International Relief Organization |
| IRO | Indian Robotics Olympiad (Bangalore, India) |
| IRO | Interim Receiving Order (UK courts) |
| IRO | Interest Rate Option |
| IRO | Independent Rental Owners |
| IRO | Institution of Railway Operators (UK) |
| IRO | Internal Review Office |
| IRO | Industrial Relations Office |
| IRO | In Region Of |
| IRO | International Regulatory Outlook (FSA, London, UK) |
| IRO | International Relief Officer (airlines) |
| IRO | Independent Research Organization |
| IRO | United Nations International Refugee Organization |
| IRO | Instructor Rated Operator |
| IRO | Incident Response Operations (NRC) |
| IRO | Isolant Rigide Ordinaire (French: Stiff Ordinary Insulation) |
| IRO | Investment Research Outsourcing |
| IRO | Insulated Uranium Oxide |
| IRO | Independent Review Officer/Office |
| IRO | Istanbul Turist Rehberleri Odasi (Turkey, Istanbul tourist guides union) |
| IRO | Internal Replenishment Order (Inventory Control Application Systems) |
| IRO | Indian Research Organisation |