| CrowdCircus GmbH | |
| CRT software | Carinthia |
| CRYPTAS IT-Security GmbH | Vienna |
| Crypto Management GmbH | |
| CryptoExplorer GmbH | |
| crystalsol GmbH | |
| CSO.net | Vienna |
| CSO.Net Telecom Services GmbH | Vienna |
| CSS4YOU | Vienna |
| CUBiT IT Solutions GmbH | Vienna |
| Currencyapi.com | |
| Currencylayer API | |
| Cutanos GmbH | |
| CWL Computer GmbH | Lower Austria |
| CYAN Networks Software GmbH | Vienna |
| Cyber-Atelier, Sascha Pollak KG | Lower Austria |
| Cyberhouse GmbH & Co. KG | Upper Austria |
| Cyberith GmbH | |
| Cybertec PostgreSQL International GmbH | Lower Austria |
| CYBERTRAP Software GmbH | |
| CyberTron Telekom AG | Vienna |
| D-Seven, Design und Werbeagentur e.U. | Vienna |
| Danube Private University | |
| Danube Tech GmbH | |
| Darwin’s Lab GmbH | |
| Das Comitee GmbH | |
| Das Packhaus | |
| Data Dealer | Vienna |
| Data.gv.at | Vienna |
| Datadialog.net | |
| Datadive | Vienna |
| dataformers GmbH | |
| Datagnion GmbH | |
| Dataphone GmbH | Vienna |
| DataScience Service GmbH | |
| DataScience Service GmbH | |
| Datavisyn GmbH | |
| Dataware Handelsges.m.b.H. | Lower Austria |
| Datenkraft GmbH | Styria |
| daz Design und Grafik e.U. | Tyrol |
| DBConcepts GmbH | Vienna |
| DCCS GmbH | Styria |
| DealMatrix GmbH | |
| DECOM Softwareentwicklung GmbH & Co. KG | Upper Austria |
| DeepOpinion | |
| Delegate Technology GmbH | Vienna |
| Delta 4 GmbH | |
| Demmel Products GmbH | Vienna |
| Denzel Bank | Vienna |
| Der querdenker | Salzburg |