| ONYX Apps | 🍎 | 1 | 4.7★ | Music |
| OOKBEE U COMPANY LIMITED | 🍎 | 1 | 4.5★ | Entertainment |
| OPTIMUM ENDUSTRIYEL TEMIZLIK VE KIMYASAL URUNLER SANAYI TICARET ANONIM SIRKETI | 🍎 | 1 | 4.5★ | Photo & Video |
| ORBITECH PTE. LTD. | 🍎 | 1 | 4.6★ | Social Networking |
| ORCAT PTE. LTD. | 🍎 | 1 | 4.5★ | Games |
| ORGANIZEAT LTD | 🍎 | 1 | 4.8★ | FOOD_AND_DRINK |
| OUPLUS TECHNOLOGY CO.,LIMITED | 🍎 | 1 | 4.8★ | Games |
| OWL GAMES LTD | 🍎 | 1 | 4.6★ | Games |
| OakTree Software, Inc. | 🍎 | 1 | 4.8★ | Reference |
| Oasis Games LTD | 🍎 | 1 | 4.9★ | GAMES_WORD |
| Oatmeal Apps | 🍎 | 1 | 4.8★ | Lifestyle |
| Obimy inc. | 🍎 | 1 | 4.5★ | Lifestyle |
| Oceanhouse Media | 🍎 | 1 | 4.6★ | Book |
| Octodev Ltd | 🍎 | 1 | 4.6★ | Music |
| OfferUp Inc. | 🍎 | 1 | 4.8★ | Shopping |
| Office Create Corp. | 🍎 | 1 | 4.1★ | Games |
| OkCupid | 🍎 | 1 | 4.3★ | Lifestyle |
| Okko OOO | 🍎 | 1 | 4.7★ | Entertainment |
| Old Man Sitting LLC | 🍎 | 1 | 4.3★ | Social Networking |
| Oleksandr Godoba | 🍎 | 1 | 4.0★ | Games |
| Oleksandr Pylaiev | 🍎 | 1 | 4.6★ | Music |
| Oleksandr Serhiienko | 🍎 | 1 | 5.0★ | Health & Fitness |
| Oleksii Diachenko | 🍎 | 1 | 4.4★ | Games |
| Oleksii Hohol | 🍎 | 1 | 4.7★ | Games |
| Olena Bachurina | 🍎 | 1 | 4.9★ | Education |
| Olleyo Games | 🍎 | 1 | 4.9★ | Games |
| Olosho LLC | 🍎 | 1 | 4.3★ | Lifestyle |
| Olson Applications Limited | 🍎 | 1 | 4.7★ | Health & Fitness |
| Olson Meditation and Mindfulness Apps Ltd | 🍎 | 1 | 4.8★ | Health & Fitness |
| Omega Labs, LLC | 🍎 | 1 | 4.8★ | Health & Fitness |
| OmniDream Limited | 🍎 | 1 | 4.9★ | Games |
| Omoroki | 🍎 | 1 | 4.6★ | Entertainment |
| Omron Healthcare, Inc. | 🍎 | 1 | 4.7★ | Health & Fitness |
| On Hand Apps - FZCO | 🍎 | 1 | 4.5★ | Business |
| One Pixel Studio | 🍎 | 1 | 4.6★ | Entertainment |
| OneUnity Digital Development Limited | 🍎 | 1 | 4.2★ | Photo & Video |
| OneWorld LLC | 🍎 | 1 | 4.7★ | Games |
| Onecent Technology Co., Limited | 🍎 | 1 | 4.7★ | Games |
| Onefootball GmbH | 🍎 | 1 | 4.8★ | Sports |
| Onekitty International Limited | 🍎 | 1 | 4.5★ | Photo & Video |
| Oni Gaming | 🍎 | 1 | 4.8★ | Games |
| Online Classifieds AG | 🍎 | 1 | 4.3★ | Lifestyle |
| Online Pianist | 🍎 | 1 | 4.4★ | Music |
| Ookla | 🍎 | 1 | 4.9★ | Utilities |
| Opal OS | 🍎 | 1 | 4.8★ | Productivity |
| Open Dating Media LTD. | 🍎 | 1 | 4.5★ | Social Networking |
| Open Education, LLC | 🍎 | 1 | 4.7★ | Education |
| Open Inc. | 🍎 | 1 | 4.9★ | Health & Fitness |
| OpenAI OpCo, LLC | 🍎 | 1 | 4.8★ | GAMES |
| OpenPhone Technologies Inc | 🍎 | 1 | 4.5★ | Business |