| Acronym | Definition |
|---|
| RIA | Regulatory Impact Assessment |
| RIA | Rock Island Arsenal (US Army) |
| RIA | Regulatory Impact Analysis |
| RIA | Rialto (Amtrak station code; Rialto, CA) |
| RIA | Rights in Action (various organizations) |
| RIA | Research in Action |
| RIA | Registered Investment Advisor |
| RIA | Rich Internet Application |
| RIA | Royal Irish Academy |
| RIA | Radioimmunoassay |
| RIA | Research and Innovation Actions (Horizon 2020; EU) |
| RIA | Radiation Induced Attenuation (optical fibers) |
| RIA | Rich Internet Applications |
| RIA | Relay Interface Adapter |
| RIA | Revue d'Intelligence Artificielle (French: Journal of Artificial Intelligence) |
| RIA | Russian Information Agency |
| RIA | Research Institute on Addictions |
| RIA | Rottnest Island Authority (Australia) |
| RIA | Research Institute of America (tax research firm) |
| RIA | Rare Isotope Accelerator |
| RIA | Robotics Industries Association |
| RIA | Risk Impact Assessment |
| RIA | Railway Industry Association (UK) |
| RIA | Regional Integration Arrangement (various organizations) |
| RIA | Reactivity-Initiated Accident |
| RIA | Radiosonde Initial Analysis |
| RIA | Research Initiation Award |
| RIA | Revue de l'Industrie Agroalimentaire (French: Journal of the Food Industry) |
| RIA | Radioiodine Ablation |
| RIA | Related Instructor Activity (US Navy) |
| RIA | Reactivity Insertion Accident |
| RIA | Régiment d'Infanterie Alpine (French: Alpine Infantry Regiment) |
| RIA | Rich International Airways (Miami, Florida) |
| RIA | Regional Internet Australia |
| RIA | Rapid Impact Assessment |
| RIA | Runway Independent Aircraft |
| RIA | Remote Internet Access |
| RIA | Registered Industrial Accountant (Canada) |
| RIA | Relativistic Impulse Approximation |
| RIA | Random Insanity Alliance (gaming clan; Cyber Nations) |
| RIA | Revolution in Intelligence Affairs |
| RIA | Regional Inuit Association (Canada) |
| RIA | Robinets d'Incendie Armé (French fire extinguisher) |
| RIA | Right Iliac Artery |
| RIA | Rosettanet Integration Architecture |
| RIA | Resource Impact Assessment |
| RIA | Range Insensitive Axis |
| RIA | Rack Interface Agreement |
| RIA | Recommended Improvement Area |
| RIA | Regional Incentive Agreement (Government pricing agreement term) |
| RIA | Rheumatology, Immunology and Allergy Division (various locations) |
| RIA | Réseau Incendie Armée |
| RIA | Réunions Internationales d'Architectes (French: International Meetings of Architects) |
| RIA | Reserve Intelligence Unit |
| RIA | Roofing Installation Application |
| RIA | Reprogramming Interface Assembly |