| CyberShack | New South Wales |
| Cyclomedica Australia Pty Ltd | |
| Cyclotek | |
| Cygnet Securities Australia Pty Ltd | Victoria |
| Cymax Pty Ltd | Queensland |
| Cynata Therapeutics | |
| Cynch Sec Pty Ltd | Victoria |
| Cynergic Pty Ltd | Victoria |
| Cypher Research Laboratories Pty Ltd | Queensland |
| CyRise | Victoria |
| Cyrius Media Group Pty Ltd | New South Wales |
| Cyteph | |
| D-Link Australia | New South Wales |
| D.P. Web Design | Queensland |
| D.R.A. Computing Pty Ltd | South Australia |
| Daemon | New South Wales |
| Daisee | New South Wales |
| Daisy Digital | |
| Daley Electronics Pty Ltd | Victoria |
| Damstra Technology | Victoria |
| Dank Designs | |
| Dapper Apps | |
| Dapth | |
| Dapth | |
| DART Data Entry Services Pty Ltd | New South Wales |
| Darwin Digital Agency | |
| Darwin I.T. Support | |
| Darwin Innovation Hub | |
| Darwin Office Technology | |
| Darwinium Pty Ltd | |
| Dash Designs | Queensland |
| Dash Digital | Western Australia |
| dash/hound | |
| Dashcams Direct | New South Wales |
| Data Action Pty Ltd | South Australia |
| Data Breeze | |
| Data Detect | New South Wales |
| Data Futurology | New South Wales |
| Data League | |
| Data Recovery Now | Queensland |
| Data Recovery Services | Queensland |
| Data Republic | New South Wales |
| Data Sauce | Victoria |
| Data Scientists Pty Ltd | |
| Data Zoo | |
| Data#3 Ltd | Queensland |
| Data.gov.au | Australian Capital Territory |
| DATA365 | |
| Database Consultants Australia | Victoria |
| Databasics | Queensland |