| Abbreviation | Definition |
|---|---|
| OJA | Online Journalism Awards |
| OKK | Orang Kaya-Kaya |
| OLMM | Our Lady of the Miraculous Medal (Hampton, NH) |
| OM | Order of Merit |
| OMRS | Orders and Medals Research Society |
| OOA | Orchids and Onions Awards |
| OOKB | Order of the Omujwaara Kondo of Bunyoro-Kitara Kingdom |
| OOP | Order Of the Palm |
| OOPA | Outstanding Office Professional Award |
| OOR | Officer of the Order of the Rokel |
| OP | Outstanding Performer |
| OPA | Office of Prestigious Awards |
| OPAL | Outstanding Philanthropic Award For Leadership |
| OPE | Optiview Protocol Expert |
| OPEA | Ontario Professional Engineers Awards |
| OPSA | OSSTMM Professional Security Analyst |
| OPST | OSSTMM (Open Source Security Testing Methodology Manual) Professional Security Tester |
| OQA | Oregon Quality Award |
| ORA | Online Retail Awards |
| ORCA | Oregon Readers Choice Award |