| Carola Zentara | |
| Cashcom Abrechnungssysteme GmbH | Tyrol |
| CashPilot | |
| Cashy GmbH | |
| CelestialBytes IT-Solutions | |
| Celix Solutions GmbH | Vienna |
| Cellectric Biosciences | |
| Celum GmbH | Upper Austria |
| CeMM Forschungszentrum für Molekulare Medizin GmbH der Österreichischen Akademie der Wissenschaften | |
| Center for Integrative Bioinformatics Vienna | Vienna |
| Center for Usability Research & Engineering | Vienna |
| Central European University - Department of Network and Data Science | |
| Centrovox Kabelvertriebs Gesellschaft m.b.H. | Lower Austria |
| CEYONG GmbH | |
| cFactural | |
| CG Shop e.U. | Vienna |
| Chaka2 GmbH | |
| Chatlyn | |
| CHCNET Hosting & Coding | Lower Austria |
| Chilly.domains | Salzburg |
| ChironWells GmbH | |
| Chris Hager | Vienna |
| Christoph Wille | Styria |
| ChromoSoft | Upper Austria |
| CIIT GmbH | Vienna |
| Circle17 | |
| Circly | |
| Circonnact | |
| CISC Semiconductor GmbH | Carinthia |
| CLEF Elektronik Consulting GmbH | Vienna |
| Clients-Guide e.U. | |
| Climate Lab | |
| Clique | |
| ClockStone | Tyrol |
| Cloudomation | |
| CMS electronics GmbH | Carinthia |
| CO x media KG | Vienna |
| Co-Work Vienna | |
| Code Square Labs | |
| Codeaware GmbH | |
| CodeFactory Vienna | |
| Codera | |
| Codeversity GmbH | |
| Codico GmbH | Lower Austria |
| Cogvis Software und Consulting GmbH | |
| Colenta Labortechnik GmbH & Co. KG | Lower Austria |
| Colorful | |
| Colorphyll GmbH | |
| Colpari | |
| Combeenation GmbH | Upper Austria |