| FIRS | Falkland Islands Radio Service 
| Others |
| FIRS | Family Intervention and Restorative Services
| Others |
| FIRS | Far Infra Red Sauna
| Others |
| FIRS | Far-Infrared Spectroscopy Group
| Others |
| FIRS | Federal Information Relay Service
| Others |
| FIRS | Federal Inland Revenue Service
| Others |
| FIRS | Federal Inland Revenue Services
| Others |
| FIRS | Federal Interstate Registration Scheme
| Others |
| FIRS | Federated Internet Registry Service
| Others |
| FIRS | Federation Internationale de Roller Skating
| Others |
| FIRS | Fetal Inflammatory Response Syndrome
| Others |
| FIRS | Field Investigative Reporting System
| Others |
| FIRS | Financial Information Reporting System
| Others |
| FIRS | Financial Information Retrieval System
| Others |
| FIRS | Financial Intermediation Research Society
| Others |
| FIRS | Fondation Internationale de Recherche Servier
| Others |
| FIRS | Foothills Information Referral Services
| Others |
| FIRS | Forensic Investigation Research Station
| Others |
| FIRS | FORSCOM Issue Resolution System
| Others |
| FIRS | Forum of International Respiratory Societies
| Others |
| FIRS | Industry Replacement Set
| Others |