| Theme Press | New South Wales |
| ThemeForest | Victoria |
| Thermal Coding Australia | New South Wales |
| TheSEOExpertSydney.com.au | |
| Think Digital | South Australia |
| Think Education | |
| Think Internet | New South Wales |
| Think Safety Systems | Victoria |
| Think Talent Pty Ltd | Victoria |
| Thinkgrid | |
| ThinkingRock | New South Wales |
| Thinkroom Digital Marketing | |
| Thinkswap Pty Ltd | |
| ThinQ-shift | |
| Thirst Creative | |
| Thirteen Digital | |
| Thomas Marsden Advertising Pty Ltd | New South Wales |
| Thorn Creative | |
| ThoughtWare Australia Pty Ltd | Queensland |
| Threat Protect Asutralia Ltd | Western Australia |
| Three AM Web + IT | South Australia |
| Three Fat Fish SEO | |
| Three Springs Technology | |
| Thrive Digital | |
| Thriving Web Design | |
| Throttle Media | New South Wales |
| Thryv, Inc. | |
| TI Systems | Western Australia |
| Tiberius Data Mining | Victoria |
| Tic Technologies | New South Wales |
| Tick Tock Design | Victoria |
| Tickit Systems Pty Ltd | New South Wales |
| Tidal Ventures | New South Wales |
| TidyHQ | Victoria |
| Tier-3 Pty Ltd | New South Wales |
| Tiliter | New South Wales |
| Till Payments | New South Wales |
| Time & Access Systems | New South Wales |
| Timesheets MTS Software | South Australia |
| Timetabling Solutions | Victoria |
| TinaCMS | |
| Tindo Solar | South Australia |
| Tissue Repair Ltd | |
| Titan Blue Australia | |
| Tixel Pty Ltd | |
| TMD Online | Queensland |
| TMQ International Pty Ltd | Queensland |
| TN3 Productions | Western Australia |
| Toba Data Recovery | Victoria |
| Toby Creative | |