| Acronym | Definition |
|---|
| RPSI➣Rheinland Pfalz Saar International (horse breed) |
| RPSI➣Railway Preservation Society of Ireland |
| RPSI➣Relative Penis Size Index |
| RPSI➣Reliable Power Systems, Inc. (Castle Rock, CO) |
| RPSI➣Rapid Prototyping Society of India (est. 2001) |
| RPSI➣Retriever Payment Systems, Inc. (Houston, TX) |