| Tape It Music GmbH | |
| Tapline | |
| Taquiri | Hesse |
| TARA Systems GmbH | Bavaria |
| Tarent Solutions GmbH | Hesse |
| Target Global | Berlin |
| Target Partners | Bavaria |
| Target Software Solution GmbH | Baden-Württemberg |
| Target Training GmbH | |
| Targomo Casafari GmbH | |
| TargoSoft IT-Systemhaus GmbH | North Rhine-Westphalia |
| Taros Chemicals GmbH & Co. KG | |
| Tarox AG | |
| Tascan Service GmbH | North Rhine-Westphalia |
| Taskit GmbH | Berlin |
| TasSpaces UG (haftungsbeschränkt) | Bavaria |
| tataga Consulting | North Rhine-Westphalia |
| Taube - Digitale Archivierungssysteme GmbH | North Rhine-Westphalia |
| Taube Electronic GmbH | Berlin |
| Taubner Network Solutions GmbH | Thuringia |
| Taunuslicht Optoelektronik GmbH | Hesse |
| TauroPharm GmbH | |
| Taurus Consult Hamburg | |
| Tawny GmbH | |
| Taxdoo GmbH | |
| Taxdoo GmbH | |
| Taxfix | Berlin |
| Taxfix SE | |
| Taxy.io GmbH | |
| TaylorCom Softwareentwicklung Ltd | North Rhine-Westphalia |
| TB-Solutions Boob&Bruns GbR | Saxony |
| TB-Tec GmbH | Saarland |
| tbd* | |
| TBG Telefon Bau GmbH | Saxony-Anhalt |
| TBit Torsten Berting it GmbH | |
| TBJ-Dynamische Messtechnik | Bavaria |
| TBK – Technisches Büro Kühnhold | |
| TBN GmbH | Baden-Württemberg |
| TBR Automation & Systemsoftware | Hesse |
| TBS Printware Vertriebs GmbH | Hesse |
| TBSoft Hans Moser e.K. | Baden-Württemberg |
| TBZ-PARIV GmbH | Saxony |
| TC Unterhaltungselektronik AG | Rhineland-Palatinate |
| TCB Hard + Software GmbH | North Rhine-Westphalia |
| Tchernov Audio GmbH | |
| TCMSOFT | |
| TCS Technische Computer Systeme Süssen GmbH | Baden-Württemberg |
| TD-Networks GmbH | |
| TDK-Micronas GmbH | Baden-Württemberg |
| TDM Systems GmbH | Baden-Württemberg |