| RISA | Racing Information Services Australia 
| Others |
| RISA | Radioactive Iodine Serum Albumin
| Others |
| RISA | Rapid Imaging Spectrophotometric Array
| Others |
| RISA | Rapid Interactive Structural Analysis
| Others |
| RISA | Recording Industry of South Africa
| Others |
| RISA | Reflux Infants Support Association
| Others |
| RISA | Regional Integrated Sciences and Assessments
| Others |
| RISA | Regional Integrated Sciences Assessments
| Others |
| RISA | Relevant Inspiring Specific and Accurate
| Others |
| RISA | Religion In South Asia
| Others |
| RISA | Resource Industry Suppliers Association
| Others |
| RISA | Retrosigmoid Intradural Suprameatal Approach
| Others |
| RISA | Rhode Island Soccer Association
| Others |
| RISA | Rhode Island Songwriters Association
| Others |
| RISA | Rionet Intelligence Sophisticated Amenity
| Others |
| RISA | Rotterdam International Students Association
| Others |