| REI | Racial Equity Institute 
| Others |
| REI | Radio Engineering Industries
| Others |
| REI | Rain Eri Isabel
| Others |
| REI | Range From Entry Interface (400 K)
| Others |
| REI | Re Entry Interval
| Others |
| REI | Reaction Engineering International
| Others |
| REI | Reading Every Index
| Others |
| REI | Real Equipment Impossible
| Others |
| REI | Real Estate Investing
| Others |
| REI | Real Estate Investment
| Others |
| REI | Real Estate Investments
| Others |
| REI | Real Expensive Items
| Others |
| REI | Really Expensive Items
| Others |
| REI | Recommended Exposure Index
| Others |
| REI | Recreational Equipment Inc
| Others |
| REI | Recreational Equipment Incorporated
| Others |
| REI | Recreational Equipment International
| Others |
| REI | Recreational Equipment, Inc.
| Others |
| REI | Recreational Equipment, Incorporated
| Others |
| REI | Red de Empresas de Internet
| Others |
| REI | Regina, French Guiana
| Others |
| REI | Regular Education Initiative
| Others |
| REI | Release Eligible Inmate
| Others |
| REI | Reliable Effective and Innovative
| Others |
| REI | Remote Error Indicator
| Others |
| REI | Renewable Energy International
| Others |
| REI | Renta Electronic Invoice
| Others |
| REI | Reproductive Endocrinology and Infertility
| Others |
| REI | Reproductive Endocrinology Infertility
| Others |
| REI | Research and Educational Institute
| Others |
| REI | Research Electronics International
| Others |
| REI | Research Engineers International
| Others |
| REI | Reset Indication
| Others |
| REI | Resource Exchange International
| Others |
| REI | Resources in Education Index
| Others |
| REI | Restricted Entry Interval
| Others |
| REI | Restrictive Entry Intervals
| Others |
| REI | Return Equipment Immediately
| Others |
| REI | Return Every Item
| Others |
| REI | Rhythmic Entrainment Intervention
| Others |
| REI | Ring Energy Inc
| Others |
| REI | Rochester Electronics, Incorporated
| Others |
| REI | Runway End Identification
| Others |
| REI | Rutgers Energy Institute
| Others |