| Communications Regulatory Authority | Governmental Institutions |
| Computer Arabia W.L.L. | Information Technology |
| Computer World | Conglomerates |
| Concorde Hotel Doha | Leisure and Tourism |
| Confidence Engineering and Development Company | Construction |
| ConocoPhillips Qatar Ltd | Oil and Gas |
| Conserved Foodstuffs Distribution Company W.L.L. | Food and Beverages |
| Consolidated Gulf Company | Information Technology |
| Construction Commissioning Maintenance Services WLL | Construction |
| Construction Dynamics LLC | Construction |
| Consulting Engineering Group | Construction |
| Container Freight Station | Conglomerates |
| Contraco WLL | Construction |
| Contrade Company Trading and Contracting | Construction |
| Control Contracting & Trading Co. (Pvt.) Qatar | Conglomerates |
| Contromet W.L.L | Construction |
| Convert Engineering & Trading | Construction |
| Conxion Logistics & Heavy Equipments | Transport |
| COREO | Real Estate |
| Country Rent A Car | Transport |
| Cozmo Travel Qatar | Leisure and Tourism |
| Creative Action Design LLC | Services |
| Creative Rent A Car & Transport, Trading Co WLL | Conglomerates |
| Creo Co | Power and Utilities |
| Crompton International Trading & Contracting Company W.L.L. | Construction |
