| MRTA | Macedon Ranges Tennis Association 
| Others |
| MRTA | Manitoba Recreational Trails Association
| Others |
| MRTA | Maple Ridge Teachers' Association
| Others |
| MRTA | Marihuana Regulation and Taxation Act
| Others |
| MRTA | Marijuana Regulation and Taxation Act
| Others |
| MRTA | Marketable Record Title Act
| Others |
| MRTA | Maryland Retired Teachers Association
| Others |
| MRTA | Mass Rapid Transit Authority
| Others |
| MRTA | Mechanical Response Tissue Analyzer
| Others |
| MRTA | Metropolitan Rapid Transit Authority
| Others |
| MRTA | Michigan Retired Teachers Association
| Others |
| MRTA | Miramichi River Tourism Association
| Others |
| MRTA | Missouri Retired Teachers Association
| Others |
| MRTA | Montachusett Regional Transit Authority
| Others |
| MRTA | Mortgage Reducing Term Assurance
| Others |
| MRTA | Mountain Rides Transportation Authority
| Others |
| MRTA | Movimiento Revolucionario Tupac Amaro
| Others |
| MRTA | Multi Robot Task Allocation
| Others |
| MRTA | Tamarindo de Bagaces, Costa Rica
| Others |