| DSL Electronic GmbH | North Rhine-Westphalia |
| DSL-City-Shop.de | Baden-Württemberg |
| DSN Holding GmbH | Bremen |
| dSPACE digital signal processing and control engineering GmbH | North Rhine-Westphalia |
| DSW-Consulting GmbH | |
| DT Netsolution GmbH | Baden-Württemberg |
| DTE Automation GmbH | North Rhine-Westphalia |
| dtm Datentechnik Moll GmbH | |
| DTMS Deutsche Telefon- und Marketing Services AG | Rhineland-Palatinate |
| DTP-Internet | Baden-Württemberg |
| Duale Hochschule Baden-Württemberg | Baden-Württemberg |
| Duale Hochschule Baden-Württemberg Villingen-Schwenningen | |
| Dualkonzept OHG | Bremen |
| Dualutions GmbH | North Rhine-Westphalia |
| DUB Business Software | Bavaria |
| Dubidoc | |
| Ducktrain | North Rhine-Westphalia |
| DueDash Capital Networks GmbH | |
| Duisburger Linux User Group | North Rhine-Westphalia |
| Dupp Datensysteme GmbH | Hesse |
| Durchstarten im Internet e.K. | |
| Durmus IT Consulting & Solutions | North Rhine-Westphalia |
| DÜRR Group GmbH | Baden-Württemberg |
| Durststrecke GmbH i. L. | Baden-Württemberg |
| Duske Technologies Gmbh | |
| Dv idee edv beratungsgesellschaft mbH | Lower Saxony |
| DV-Treff | North Rhine-Westphalia |
| DVB viewer | Thuringia |
| DVC Software + Service GmbH | Lower Saxony |
| DVD Datenverarbeitung & -dienstleistung GmbH | North Rhine-Westphalia |
| DvH Ventures | North Rhine-Westphalia |
| DVS System Software GmbH & Co. KG | North Rhine-Westphalia |
| dx.one GmbH | |
| dxFeed | |
| DyeMansion GmbH | |
| Dymatrix Consulting Group GmbH | |
| DyNAbind GmbH | |
| Dynabit Systemhaus GmbH | Berlin |
| DynaForms GmbH | North Rhine-Westphalia |
| DynaGeo | Baden-Württemberg |
| Dynamic Lines GmbH | Bavaria |
| Dynamic Net Solutions | |
| Dynamic Net Solutions GmbH | Hesse |
| Dynamic Software AG | Bavaria |
| Dynamicdrive GmbH & Co. KG | Saxony |
| Dynamics Consulting GmbH | |
| DYNAMIS Batterien GmbH | |
| DynaPictures GmbH | |
| DZ Bank AG | Hesse |
| DZB Bank GmbH | Hesse |