| ComFin Software GmbH | |
| Commend International GmbH | Salzburg |
| Commitly GmbH | |
| Compass-Verlag GmbH | Vienna |
| Compuritas GmbH | |
| Computer & Communication | Vienna |
| Computer Center Lorentschitsch GmbH | Salzburg |
| Computer Tscheme | Styria |
| Computerambulanz | Vienna |
| ComputerCompetence.at | |
| Computerhilfe-Nachfülltinte | Styria |
| Comtech IT-Solutions GmbH | Lower Austria |
| CONDA Unternehmensberatungs GmbH | Vienna |
| Connecting Software | |
| conneXion Trawöger, Schwarz OG | Tyrol |
| Conova Communications GmbH | Salzburg |
| Conrad Electronic GmbH & Co. KG | Upper Austria |
| Consens Zeiterfassung GmbH | Tyrol |
| consola.finance | |
| Consoleplus.com | Lower Austria |
| Consolidate Software GmbH | Vorarlberg |
| Constantia New Business GmbH | |
| CoPlanner Software & Consulting GmbH | Styria |
| CoreShop GmbH | |
| CoreTEC IT Security Solutions GmbH | Vienna |
| COREX EDV-Dienstleistungen GmbH | Vienna |
| Cortical.io | Vienna |
| Coworking Wildgarten | |
| CPU Informatik GmbH | Tyrol |
| CreativeFuture KG | Styria |
| Credi2 | |
| Crosat Austria GmbH | Vienna |
| Crosseye Marketing GmbH | Styria |
| Crossip Communications GmbH | Vienna |
| CrowdCircus GmbH | |
| CRT software | Carinthia |
| crwlr.software | |
| CRYPTAS IT-Security GmbH | Vienna |
| 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 |
| Cyathus Exquirere Pharmaforschungs GmbH | |
| Cyber-Atelier, Sascha Pollak KG | Lower Austria |