| Nokhba Travels &Tours | Leisure and Tourism |
| Noors Engineering WLL | Conglomerates |
| Noors Trading | Construction |
| North Ocean Company W.L.L. | Transport |
| Northwestern University in Qatar | Education |
| O.T.S. Cleaning Co. W.L.L | Services |
| Oasis Cars | Transport |
| Oasis Elevators Company WLL | Services |
| Obaikan Equipment & Services W.L.L | Industrial Manufacturing |
| OCS Qatar LLC | Real Estate |
| Octogone Qatar WLL | Industrial Manufacturing |
| Off Road WLL | Services |
| Oilfield Projects Dev Co Wll ( Opd Group) Qatar | Conglomerates |
| OITC Group W.L.L | Construction |
| OITC Travel & Toursim | Leisure and Tourism |
| Olympic Sports Company W.L.L | Retail |
| Omega Engineering W.L.L | Construction |
| Omni Collection | Industrial Manufacturing |
| Oneteam Clothing Company | Retail |
| Oola Sports LLC | Retail |
| OOREDOO Q.S.C. | Telecommunications |
| Opticsense | Telecommunications |
| Optimum Systems W.L.L. | Information Technology |
| Orbit Trading & Contracting Co. | Construction |
| Oriental Trading Company Limited | Industrial Manufacturing |
