| Gbekeloluwa | Oguntimein | Morgan State University | United States | Environmental Science | Wastewater | worldtopscientists.com |
| TOSHIFUMI | OHKUSA | juntendo | Japan | Immunology and Microbiology | Medicine | worldtopscientists.com |
| THERESA UGONWA | OKAFOR | CHUKWUEMEKA ODUMEGWU OJUKWU UNIVERSITY IGBARIAM CAMPUS NIGERIA | Nigeria | Other | PHYSICS EDUCATION | worldtopscientists.com |
| Olawale | Ola | University of Ibadan | Nigeria | Veterinary Science and Veterinary Medicine | Veterinary Pathology | worldtopscientists.com |
| Alexsandra Duarte de | Oliveira | Embrapa Cerrados | Brazil | Agricultural and Biological Sciences | Agrometeorologia/mudanças climáticas | |
| Marilene | Oliveira | unifesspa | Brazil | Chemistry | Química Orgânica/Química de Produtos Naturais/Química d emicrorganismo | |
| Gea Marzia | Oliveri Conti | University of Catania | Italy | Medicine and Dentistry | Environmental health | worldtopscientists.com |
| Abiodoun Pascal | OLOUNLADE | National University of Agriculture | Benin | Agricultural and Biological Sciences | Biochemistry, Pharmacognosy, Zootechnics | worldtopscientists.com |
| Štefan | Ondočko | Technical University of Košice | Slovakia | Engineering | Department of Production Systems and Robotics | worldtopscientists.com |
| Chinna | Orish | University Of Portharcourt Neuroscience Group | Nigeria | Neuroscience | NEUROTOXICOLOY | worldtopscientists.com |
| Bernard Eze | Orji | Alex Ekwueme Federal University, Ndufu-Alike Ebonyi State | Nigeria | Arts and Humanities | Theatre and Cultural Studies | worldtopscientists.com |
| Muhammad | Osman | King Saud University | Saudi Arabia | Physics and Astronomy | Thin film - Solar cells - Perovskite - Material Science | worldtopscientists.com |
| Magda | Osman | University of Cambridge/University of Leeds | United Kingdom | Social Sciences | Judgment and Decision Making | worldtopscientists.com |
| Martin | Ostoja-Starzewski | University of Illinois at Urbana-Champaign | United States | Engineering | mechanics | worldtopscientists.com |
| María Angélica | Ouellette | Lakeland Agricultural Research Association | Canada | Agricultural and Biological Sciences | Weed Science | worldtopscientists.com |
| Chourouk | Ouerghemmi | Chaire de recherche en Technologie, Durabilité et Société (Chaire TDS) à l'Université du Québec à Chicoutimi (UQAC) | Canada | Business, Management and Accounting | Marketing | worldtopscientists.com |
| Chourouk | OUERGHEMMI | Chaire TDS - UQAC | Canada | Business, Management and Accounting | Marketing | worldtopscientists.com |
| Sulman | Owili | Department of Agricultural Economics, University of Nairobi | Kenya | Economics, Econometrics and Finance | Agricultural Economics | worldtopscientists.com |
| Michael | Owusu Ansah | Division of Agricultural and Applied Economics, University of Missouri-Columbia | United States | Agricultural and Biological Sciences | Agricultural and Applied Economics | worldtopscientists.com |
| Sunday Olayinka | Oyedepo | Bells University of Technology | Nigeria | Engineering | Mechanical Engineering | worldtopscientists.com |