| Oberoi Hotels & Resorts 1800112030 |
| Oceanic Consultants 18001031400 |
| Oilco Services (India) 1800112777 |
| Olive 180026665483 |
| Olive Mobiles 18004208282 |
| Om Radianz Infra 18001032299 |
| Om Sai Ayurveda 1800117841 |
| Om Sai Global 18001032424 |
| Omega Watches 1800119191, 18001029191 |
| Omnilife India 18002006664 |
| One For All 18001023299 |
| Online Grievance Information System (OGIS), Haryana 18001802200 |
| Oracle 18004256725 18006330738 |
| Oracle Education / Oracle University Training Centers India 18004258877 |
| Orchid Hotel 1800225432 |
| Oriensoft Technologies 1800225171 |
| Orient Flight School 18004254359 (IFLY) |
| Oriental Bank of Commerce 18003452424 18001801235 |
| Oriental Insurance 18004252002, 18001026425 |
| Orion Mobiles 18001033330 |
| Ortel Communications 18004196060 |
| Oster 18001026300 |
| Oxford Software Institute 1800117799 |
