| Ohio Journalists | 6872 | |
| Opera Journalists | 6421 | |
| Orlando Journalists | 3682 | |
| Opinion Journalists | 2004 | |
| Oregon Journalists | 1653 | |
| Oklahoma Journalists | 1500 | |
| Oklahoma City Journalists | 1384 | |
| Outdoor Journalists | 967 | |
| Obesity Journalists | 504 | |
| Ovarian Cancer Journalists | 449 | |
| Oakland Journalists | 364 | |
| Oil And Gas Journalists | 305 | |
| Orthodontic Journalists | 213 | |
| Online Business Journalists | 206 | |
| Overland Park Journalists | 150 | |
| Olympics Journalists | 106 | |
| Organizing Journalists | 90 | |
| Organic Beauty Journalists | 86 | |
| Office 365 Journalists | 82 | |
| Organic Food Journalists | 72 | |
| Omaha Journalists | 41 | |
| Oxnard Journalists | 34 | |
| Ontario Journalists | 33 | |
| Olathe Journalists | 27 | |
| Organic Farming Journalists | 16 | |
| Origami Journalists | 15 | |
| O Tempo Journalists | | |
| Omaha World Herald Journalists | | |
| Olive Press Journalists | | |
| Oak Park Journalists | | |
| Our Midland Journalists | | |
| Orlando Weekly Journalists | | |
| Onward State Journalists | | |
| Ottawa Citizen Journalists | | |
| Observer Journalists | | |
| Oil City News Journalists | | |
| Orlando Sentinel Journalists | | |
| Otago Daily Times Journalists | | |
| Okaz Journalists | | |
| Orange County Register Journalists | | |
| Oregon Live Journalists | | |
| Open Democracy Journalists | | |
| Oye Veracruz Journalists | | |
| O Globo Journalists | | |
| Okdiario Journalists | | |
| Observador Journalists | | |
| Olean Times Herald Journalists | | |
| OU Daily Journalists | | |
| Observer Uganda Journalists | | |
| Oakland Press Journalists | | |
