| O Connors Irish And UK Fish And Chips | Restaurants | O Woolcox | Farming |
| O'Shaman Andre Parker | Human Resources | O. Kay Knibbs | Real Estate |
| O.C.D. Experience | Consumer Services | Oakleaf Highlands | Retail |
| Oakley Roofing And Construction | Construction | Oaks Early Learning Center | Education |
| Oana Balan | Media Production | Oana Cancel | Accounting |
| Oana Puscas | Law Practice | Oana Raluca Voican | Marketing and Advertising |
| Oana Schone | Accounting | Oancea Marian | Computer Software |
| Oancea Monica | Accounting | Oasys Tss | Professional Training & Coaching |
| Oğuz Burak Şipşak | Computer Software | Oğuzhan Cabbaroğlu | Graphic Design |
| Obaid Ahmed | Obaid Khan | Accounting | |
| Obaidullah Babar | Construction | Obasidey Tony | Accounting |
| Obed Eugene | Obed Remy | ||
| Obed Remy | Obi Wilson | Security and Investigations | |
| Obinna Isiadinso | Venture Capital & Private Equity | Oblivious Author | Entertainment |