| Abbreviation | Definition |
|---|---|
| OHMS | Omron Health Management Software |
| OHRRPGCE | Official Hamster Republic Role Playing Game Construction Engine |
| OIAB | Office In A Box |
| OIK | Option Installation Key |
| OJ | Open Java |
| OJAI | Open JSON Application Interface |
| OJI | Open JVM (Java Virtual Machine) Integration |
| OJS | Open Journal Software |
| OJS | Open Journal Systems (open-source software for the management of peer-reviewed academic journals) |
| OKAY | Object Kit Across Yaml |
| OKS | Ontopia Knowledge Suite |
| OLA | Online Authorization |
| OLE | Observable Language Editor |
| OLE | Office Linking Environment |
| OLH | Outlook Helper |
| OLLY | Organized Life and Learning Yearbook |
| OLR | Off Line mail Reader |
| OLT | Open Loop Testing |
| OLT | OverLoad Test |
| OLTC | Online Authorisation and Transaction Capture |