| ROII | RAM Optical Instrumentation, Inc.
| Others |
| ROII | Rate Of Occupational Injuries And Illnesses
| Others |
| ROII | Relative Optical Interference Intensity
| Others |
| ROII | Requisite Organization International Institute
| Others |
| ROII | Return On Industrial Insurance
| Others |
| ROII | Return on Infrastructure Investment
| Others |
| ROII | Return on Innovation Investment
| Others |
| ROII | Return On Internet Investment
| Others |
| ROII | Return On Inventory Investment
| Others |
| ROII | Reverse Osmosis, second stage
| Others |
| ROII | Rock Oil International Incorporated
| Others |