| Acronym | Definition |
|---|
| IRT | International Relations and Trade |
| IRT | Item Response Theory |
| IRT | In Real Time (various organizations) |
| IRT | In Regard To |
| IRT | Infrared Thermometer |
| IRT | Iris Recognition Technology (biometrics) |
| IRT | Intensive Residential Treatment |
| IRT | Innovative Readiness Training (civil military program) |
| IRT | Isochronous Real Time |
| IRT | Institute of Road Transport (India) |
| IRT | Imago Relationship Therapist |
| IRT | In Reference To |
| IRT | Industriepark Region Trier (German: Trier Region Industrial Park) |
| IRT | Institute for Responsible Technology (Fairfield, IA) |
| IRT | Imagery Rehearsal Therapy (psychology) |
| IRT | Icing Research Tunnel (wind tunnel) |
| IRT | Interborough Rapid Transit (New York City subway division) |
| IRT | Interborough Rapid Transit |
| IRT | Integrated Receiver Transcoder |
| IRT | Infra Red Technology |
| IRT | Information Resources and Technology |
| IRT | Incident Response Team |
| IRT | In Regards To |
| IRT | Indiana Repertory Theatre |
| IRT | Immunoreactive Trypsinogen |
| IRT | Institute for Recruitment of Teachers |
| IRT | Ice Road Truckers (TV show) |
| IRT | Industry Round Table (various organizations) |
| IRT | International Racquetball Tour |
| IRT | Independent Review Team |
| IRT | Injury Recall Technique (applied kinesiology) |
| IRT | International Rescue Team (various locations) |
| IRT | International Registered Traveler |
| IRT | Infrared Telescope |
| IRT | Initial Response Team |
| IRT | Immediate Response Team |
| IRT | Infrared Transmitting (film) |
| IRT | Interactive Ray Tracing |
| IRT | Integrated Receiver/Transcoder |
| IRT | Inner Resonance Technologies |
| IRT | Individual Readiness Training |
| IRT | Integrated Retail Terminal |
| IRT | Initiative Riviera Technologies (France) |
| IRT | Integrated Requirements Team |
| IRT | Integrated Response Technology (clinical trials) |
| IRT | Instructional Resource Teacher |
| IRT | Income Reporting Threshold (taxation) |
| IRT | Internal Radiation Therapy |
| IRT | Instrument Rating Test |
| IRT | Integrated Remote Technology (Subsea 7) |
| IRT | Institute for Rapid Transit |
| IRT | Infinity/Radiance/Trance (gaming, Breath of Fire III) |
| IRT | Incidence Reporting Team |
| IRT | Interim Remote Terminal |
| IRT | Integrated Rendezvous Radar Target (NASA) |
| IRT | Intermediate Range Technology |
| IRT | Initial Reconditioning Test |
| IRT | In-Reactor Thimble (Fast Test Reactor) |
| IRT | Initial Reconnaissance Team |
| IRT | Intervention Response Team |
| IRT | Installation Readiness Testing |
| IRT | Industria de Radio y Televisión (Chilean Electronics) |
| IRT | In Response/Reply/Reference To |
| IRT | Investigation and Recovery Team |
| IRT | Integrated Reliability Test |
| IRT | Integrated Rail Terminal |