- Obafemi Awolowo University Ile-Ife (Nigeria)
- Obihiro University of Agriculture and Veterinary Medicine (Japan)
- Obirin University (Japan)
- Obninsk State Technical University for Nuclear Power Engineering (Russia)
- Obong University (Nigeria)
- OCAD University (Canada)
- Ocean University of China (China)
- Ochanomizu Women's University (Japan)
- October 6 university (Egypt)
- Oda Bultum University (Ethiopia)
- Odense University (Denmark)
- Odessa National Academy of Food Technologies (Ukraine)
- Odessa National I.I. Mecnikov University (Ukraine)
- Odessa National Marine University (Ukraine)
- Odessa National Maritime Academy (Ukraine)
- Odessa National Polytechnic University (Ukraine)
- Odessa State Academy of Construction and Architecture (Ukraine)
- Odessa State Medical University (Ukraine)
- Odlar Yurdu University (Azerbaijan)
- Oduduwa University (Nigeria)
- Ohka Gakuen University (Japan)
- Ohtani Women's University (Japan)
- Ohu University (Japan)
- Oita Medical University (Japan)
- Oita University (Japan)
- Oita University of Nursing and Health Sciences (Japan)
- Okanagan University College (Canada)
- Okan University (Turkey)
- Okayama Prefectural University (Japan)
- Okayama Shoka University (Japan)
- Okayama University (Japan)
- Okayama University of Science (Japan)
- Okinawa Institute of Science and Technology Graduate University (OIST) (Japan)
- Okinawa International University (Japan)
- Okinawa Prefectural University of Fine Arts (Japan)
- Okinawa University (Japan)
- Olabisi Onabanjo University (Nigeria)
- Olympia College (Malaysia)
- Oman College Of Management & Technology (Oman)
- Omar Al-Mukhtar University (Libya)
- Omdurman Ahlia University (Sudan)
- Omdurman Islamic University (Sudan)
- Omsk State Agrarian University (Russia)
- Omsk State Medicical Academy (Russia)
- Omsk State Pedagogical University (Russia)
- Omsk State Technical University (Russia)
- Omsk State Transport University (Russia)
- Omsk State University (Russia)
- onal Taipei University of Nursing and Health Sciences (Taiwan)
- Ondokuz Mayis University Samsun (Turkey)