| Nutromics Pty Ltd | |
| Nuvo Creative | Queensland |
| Nventt | Victoria |
| NW Communications | Western Australia |
| NX Marketing | |
| NXTGEN Industries | |
| NybleCraft Pyt Ltd | |
| Nyrada | New South Wales |
| O2 | New South Wales |
| O360 Solutions | |
| OAC Digital | Victoria |
| Oak Focus Software | Australian Capital Territory |
| Oak Telecom | Victoria |
| OAS Technology | New South Wales |
| Object Craft | Victoria |
| Objective US | New South Wales |
| OccuRx | Victoria |
| Ocean Impact Organisation | New South Wales |
| Ocean Office Automation Pty Ltd | New South Wales |
| Ocean Software | Victoria |
| Oceania Polytechnic Institute of Education | |
| Ocom Software | Victoria |
| Octet | New South Wales |
| October Productions | |
| Octopus Deploy | Queensland |
| Octopusbot | New South Wales |
| Offground | Victoria |
| Office Automation Pty Ltd | Western Australia |
| Office Information Australia | Western Australia |
| Office of the Australian Information Commissioner | New South Wales |
| Offis Pty Ltd | New South Wales |
| OFX | |
| Ohio Digital | |
| OKI Data (Australia) | New South Wales |
| OKMG | |
| Okra Solar Pty Ltd | |
| Olivitek Software Pty Ltd | Victoria |
| OMC International Pty Ltd | Victoria |
| Omegaa Pty Ltd | |
| OMG! Creative | Victoria |
| Omnata Pty Ltd | |
| Omni Online | |
| OmniHyper | New South Wales |
| Omninet | Western Australia |
| Omny Studio | Victoria |
| On Data | |
| On Deck Capital Australia Pty Ltd | New South Wales |
| On Point Digital Solutions | |
| On Q Recruitment | New South Wales |
| OncoRes Medical Pty Ltd | Western Australia |