| Cabaco Trading & Contracting | Conglomerates |
| CABz Transport | Transport |
| Caliber Trading Agencies & Franchising | Conglomerates |
| Caliber Trading Agencies & Franchising LLC | Real Estate |
| Candela Lighting | Retail |
| Capital Insurance Brokers L.L.C. | Financial Services |
| CARDIFF LOGISTICS WLL | Transport |
| Care Well International Trading | Information Technology |
| Carillion (Qatar) L.L.C | Construction |
| Carnegie Mellon University Qatar | Education |
| Casadel Gelato | Food and Beverages |
| CASTELLO - Cast Aluminium Company-Qatar | Industrial Manufacturing |
| Castle Constructions WLL | Construction |
| Castle for Building Materials Company | Industrial Manufacturing |
| Cedars Motors & Trading Co WLL | Conglomerates |
| Celerity Shipping & Forwarding Co WLL | Transport |
| Central Ventilation System Co WLL | Industrial Manufacturing |
| Central Ventilation Systems Co. WLL | Construction |
| Century Hotel - Doha | Leisure and Tourism |
| Century Trading & Contracting WLL | Oil and Gas |
| Century Trading and Contracting WLL Qatar | Services |
| CEVA Logistics Qatar WLL | Transport |
| Challenger Limousine & Rent a Car | Transport |
| Charlotte Trading & Contracting | Food and Beverages |
| Chebli Machinery and Construction Company | Construction |