| Acronym | Definition |
|---|
| RPI | Rensselaer Polytechnic Institute (Troy, NY, USA) |
| RPI | Ratings Percentage Index (college basketball) |
| RPI | Retail Price Index |
| RPI | Resort Parks International (Signal Hill, CA) |
| RPI | Rockwell Protocol Interface (modems) |
| RPI | Regroupement Pédagogique Intercommunal (French: Intermunicipal Education Coalition) |
| RPI | Real Property Inventory |
| RPI | Roberts Realty Investors, Inc. (Atlanta, GA) |
| RPI | Rapid Process Improvement |
| RPI | Richmond Professional Institute (Virginia) |
| RPI | Research Planning, Inc. |
| RPI | Reticulocyte Production Index |
| RPI | Railway Progress Institute |
| RPI | Revista da Propriedade Industrial (Official Gazette of the Brazilian Patent and Trademark Office; Brazil) |
| RPI | Related Proteins of the Immune System |
| RPI | Requested Packet Interval |
| RPI | Runs Per Inning (baseball) |
| RPI | Runway Point of Intercept |
| RPI | Rose Polytechnic Institute (Indiana) |
| RPI | Regional Perfusion Index |
| RPI | Repetitive Motion Injury |
| RPI | Ravalement, Peinture, Isolation (French: Cleaning, Painting, Insulation) |
| RPI | Rated Position Identifier |
| RPI | Real Polytechnic Institute |
| RPI | Roll Position Indicator |
| RPI | Red Planet Interactive Games |
| RPI | Ranking Percentage Index (sports statistic) |
| RPI | Recruiting Publicity Item (US Army) |
| RPI | Radar Precipitation Integrator |
| RPI | Races Per Incident (racing) |
| RPI | Residue Processing Initiative |
| RPI | Ridder Publications, Inc. |
| RPI | Responsive Production Inventory |
| RPI | Riviera Prestations Informatique (French: Riviera Computer Services) |
| RPI | Response Posture Immediate |
| RPI | Relay Position Indicator |
| RPI | Remarried Parents, Inc. |
| RPI | Request for Problem Investigation |
| RPI | Residual Plan of Instruction |
| RPI | Ressorts Produits Industriels (French: Springs Industrial Products) |
| RPI | Ressources Professionnelles Informatiques (French: Professional Computer Resources; Canada) |
| RPI | Repayment Protection Insurance (loans) |
| RPI | Retail Price Inflation |
| RPI | Remote Programming Interface (computing) |
| RPI | Restaurant Partners, Inc. (est. 1992) |