| OCHSNER CLINIC FOUNDATION | 🍎 | 1 | 4.7★ | Medical |
| OCLC | 🍎 | 1 | 4.8★ | Book |
| OCTA SOLUTIONS IHAB ALI AND HIS PARTNER | 🍎 | 1 | 5.0★ | Utilities |
| OCTALCODE | 🍎 | 1 | 4.5★ | Utilities |
| OCTUDIO | 🍎 | 1 | 4.4★ | Productivity |
| OCTech, LLC | 🍎 | 1 | 4.7★ | GAMES |
| OD SP ZOO | 🍎 | 1 | 4.0★ | Reference |
| ODDINKS LLC | 🍎 | 1 | 5.0★ | Productivity |
| ODDS INC., THE | 🍎 | 1 | 5.0★ | Social Networking |
| ODDVPN TECHNOLOGY LTD | 🍎 | 1 | — | Utilities |
| ODIN DAY STUDIO | 🍎 | 1 | 4.7★ | Productivity |
| ODK Media Inc. | 🍎 | 1 | 2.9★ | Entertainment |
| ODP Solutions, Inc | 🍎 | 1 | — | Finance |
| ODUWA BLOCKCHAIN SOLUTIONS LLC | 🍎 | 1 | 5.0★ | Finance |
| ODYSS LTD | 🍎 | 1 | 4.8★ | Games |
| ODYSSEUS SOFTWARE COMPANY, LLC | 🍎 | 1 | 4.6★ | Games |
| ODYSSEY DOWNTOWN, INC. | 🍎 | 1 | 4.3★ | Entertainment |
| OEGBVERLAG | 🍎 | 1 | — | Business |
| OESTE SAUDE - ASSISTENCIA A SAUDE SUPLEMENTAR SS LTDA | 🍎 | 1 | 4.3★ | Medical |
| OEngines Games LLP | 🍎 | 1 | 4.6★ | Games |
| OF Enterprises LTD | 🍎 | 1 | 5.0★ | Food & Drink |
| OF Media LLC | 🍎 | 1 | 2.7★ | Entertainment |
| OFFICE ALINA AL-TAQDIM FOR ELECTRONIC SERVICES | 🍎 | 1 | 4.6★ | Business |
| OFFICE HOLDINGS LTD | 🍎 | 1 | 4.5★ | Shopping |
| OFFICE MOVE | 🍎 | 1 | 5.0★ | Graphics & Design |
| OFFIWIZ, S.L. | 🍎 | 1 | 3.5★ | Utilities |
| OFX Group Limited | 🍎 | 1 | 4.8★ | Finance |
| OG Giveaways Corporation | 🍎 | 1 | — | SHOPPING |
| OG Incorporated | 🍎 | 1 | 4.8★ | Entertainment |
| OG Systems, LLC (CA) | 🍎 | 1 | 4.9★ | Utilities |
| OGQ Corperation | 🍎 | 1 | 4.7★ | Entertainment |
| OGUZ DELIOGLU | 🍎 | 1 | 4.9★ | Productivity |
| OGUZCAN BESERIKLI | 🍎 | 1 | — | Music |
| OH BOY Labs, LLC | 🍎 | 1 | 4.6★ | Games |
| OH NAM KWON | 🍎 | 1 | 4.8★ | Utilities |
| OKAN DONMEZ | 🍎 | 1 | — | Lifestyle |
| OKAN KAYCI | 🍎 | 1 | — | Utilities |
| OKAN KISAC | 🍎 | 1 | — | Utilities |
| OKAZ Organization for Press & Publication | 🍎 | 1 | 4.2★ | News |
| OKINAWAKEN KOKUMIN KENKO HOKEN DANTAI RENGOKAI | 🍎 | 1 | 3.2★ | Health & Fitness |
| OKKAMI INC | 🍎 | 1 | 2.3★ | Travel |
| OKLAHOMA CITY WATER UTILITIES TRUST | 🍎 | 1 | 4.7★ | Utilities |
| OKTAV GmbH | 🍎 | 1 | 4.7★ | Music |
| OKTOPUS RESERCH, TOV | 🍎 | 1 | 4.7★ | Productivity |
| OKX MALTA LTD | 🍎 | 1 | 4.6★ | Finance |
| OKX Technology Inc | 🍎 | 1 | 4.1★ | Finance |
| OKXE VIETNAM COMPANY LIMITED | 🍎 | 1 | 3.6★ | Shopping |
| OKsystem a.s. | 🍎 | 1 | 4.0★ | Social Networking |
| OLAYAN FOOD SERVICES COMPANY LTD | 🍎 | 1 | — | Food & Drink |
| OLEKSANDR SEMENIUK | 🍎 | 1 | 5.0★ | Education |