| TheraGenesis GmbH | |
| Therawis Healthcare GmbH | |
| Thermondo GmbH | |
| Thermosome GmbH | |
| Thermosphr | |
| Theseus Digital | Hamburg |
| Thesycon | Thuringia |
| Theum AG | Baden-Württemberg |
| theurer.com GmbH | Baden-Württemberg |
| Thielbeer – Agentur für Werbung & Marketing | North Rhine-Westphalia |
| Thiele & Klose GmbH | |
| Thielenhaus & Partner Agentur für Marketing GmbH | North Rhine-Westphalia |
| Thieme Compliance GmbH | Bavaria |
| Thierhoff Consulting | |
| Thiesen Hardware- und Software-Design GmbH | Hesse |
| thinformatics AG | |
| Thing Technologies GmbH | |
| thingk.systems UG (haftungsbeschränkt) | Brandenburg |
| Thingylabs GmbH | |
| Think Different GmbH | Berlin |
| think-cell Software GmbH | Berlin |
| Think.iT | |
| Think11 | |
| THINK5 GmbH | North Rhine-Westphalia |
| Thinkbox Berlin GmbH | |
| Thinkideas | |
| Thinking Objects GmbH | Baden-Württemberg |
| Thinkport GmbH | Hesse |
| Thinkprint GmbH | |
| Thinkprogressive | |
| Thinkproject Holding GmbH | Bavaria |
| Thinkproject Holding GmbH | |
| Thinksurance GmbH | |
| Thinktecture AG | Baden-Württemberg |
| ThinPrint GmbH | Berlin |
| thinXXS Microtechnology GmbH | |
| THIS IS! Digital Media Group GmbH | Lower Saxony |
| Thiscode e.K. | North Rhine-Westphalia |
| Thomas & Gilles GmbH | North Rhine-Westphalia |
| Thomas Böhme EDV | Baden-Württemberg |
| Thomas Derflinger | |
| Thomas Fischl | |
| Thomas Frütel | North Rhine-Westphalia |
| Thomas Hippchen GmbH | Saarland |
| Thomas Oltzen | North Rhine-Westphalia |
| Thomas Pelletier Web- und Printdesign | Saarland |
| Thomas Schoessow | Rhineland-Palatinate |
| Thomas Schütt | Hamburg |
| Thomas schwobe softwareentwicklung | Thuringia |
| Thomas Wollner | Hesse |