| RU | Are You .... 
| Others |
| RU | Rack Unit
| Others |
| RU | Radford University
| Others |
| RU | Radiance Unit
| Others |
| RU | Radio Userland
| Others |
| RU | Radius of Uranus
| Others |
| RU | Raffles University
| Others |
| RU | Rajshahi University
| Others |
| RU | Rambunctious Umbrellas
| Others |
| RU | Ramp Up
| Others |
| RU | Ranchi University
| Others |
| RU | Range Update
| Others |
| RU | Read Uncommitted
| Others |
| RU | Reader User
| Others |
| RU | Ready Units
| Others |
| RU | Recognition Unit
| Others |
| RU | Redeemer's University, Mowe
| Others |
| RU | Reduced Units
| Others |
| RU | Reduction Unit
| Others |
| RU | Relative Uncertainty
| Others |
| RU | Relative Units
| Others |
| RU | Release Unit
| Others |
| RU | Release Update
| Others |
| RU | Remote Unit
| Others |
| RU | Repertorium Universale
| Others |
| RU | Replaceable Unit
| Others |
| RU | Request Unit
| Others |
| RU | Rescue Unit
| Others |
| RU | Reservations Used
| Others |
| RU | Resistance Units
| Others |
| RU | Resonance Units
| Others |
| RU | Resource Unit
| Others |
| RU | Response Unit
| Others |
| RU | Responsibility Unit
| Others |
| RU | Rhodes University
| Others |
| RU | Rhodes-Universiteit
| Others |
| RU | Rhythmic Unit
| Others |
| RU | Rice University
| Others |
| RU | Rider University
| Others |
| RU | Rockefeller University
| Others |
| RU | Roses Unlimited
| Others |
| RU | Round Up
| Others |
| RU | Roussel Uclaf
| Others |
| RU | Roussel Uclaf (now part of Hoechst AG)
| Others |
| RU | Routine Urinalysis
| Others |
| RU | Rowan University
| Others |
| RU | Running Up
| Others |
| RU | Runs Up
| Others |
| RU | Rural Utopia
| Others |
| RU | Russian UK
| Others |
| RU | Russian Union
| Others |
| RU | Rustic Upbringing
| Others |
| RU | Rutgers University
| Others |
| RU | Ruthenium
| Element |
| RU | Ryerson University
| Others |