| CMS electronics GmbH | Carinthia |
| CO x media KG | Vienna |
| Co-Work Vienna | |
| Code Square Labs | |
| Codeaware GmbH | |
| CodeFactory Vienna | |
| Codeversity GmbH | |
| Codico GmbH | Lower Austria |
| Cogvis Software und Consulting GmbH | |
| Coinfinity GmbH | |
| Coinnecting | |
| Coinpanion | |
| Colenta Labortechnik GmbH & Co. KG | Lower Austria |
| Colorful | |
| Colpari | |
| Combeenation GmbH | Upper Austria |
| 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 |
| 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 | |
| Croma-Pharma GmbH | |
| Crosat Austria GmbH | Vienna |
| Crosseye Marketing GmbH | Styria |
| Crossip Communications GmbH | Vienna |