| Ms | Otgonpurev | Nergui | Nuclear Research Center, National university of Mongolia | Mongolia | Engineering | research of environmental issue, comparison of policy, engineering, physics | Best Researcher Award | environmentalscientists.org |
| Prof | Otari | Didmanidze | Departments of Tractors and Automobiles, Institute of Mechanical and Power Engineering Named After V.P. Goryachkin, Russian State Agrarian University—Moscow Timiryazev Agricultural Academy | Russia | Ecology and Conservation | Thermophysical processes of spontaneous combustion and forced ignition of solid disperse materials | Best Researcher Award | environmentalscientists.org |
| Dr | Osvaldo | Valarini Junior | Universidade Tecnológica Federal do Parana | Brazil | Chemical Engineering | Tratamento de Água e Efluentes | Best Researcher Award | environmentalscientists.org |
| Dr | Oscar Alfredo | Jaramillo Salgado | Universidad Nacional Autónoma de México | Mexico | Engineering | Renewable Energy | Excellence in Scientific Innovation Award | environmentalscientists.org |
| Mr | Osama Bin | Shafaat | Aalto University | Finland | Astronomy and Astrophysics | Remote Sensing | Best Researcher Award | environmentalscientists.org |
| Mr | Onesme | NZASABAYEZU | Gandhi Institute of Technology and Management | India | Others | Poverty Alleviation Strategies for Sustainable Development | Best Researcher Award | environmentalscientists.org |
| Dr | Omar | Sims | Cleveland Clinic | United States | Medicine and Health Sciences | Hepatology | Best Researcher Award | environmentalscientists.org |
| Dr | Oluwatoyin Joseph | Gbadeyan | Durban University of Technology, South Africa | South Africa | Environmental and Sustainable Materials | Waste valorization and Bioeconomic | Best Researcher Award | environmentalscientists.org |
| Dr | Oluwatayo | Ojo | Cranfield University | United Kingdom | Engineering | Energy Economics and Policy | Best Researcher Award | environmentalscientists.org |
| Dr | Oluwaseun | Adeniji | University of Johannesburg | South Africa | Biotechnology | Nanotechnology | Best Researcher Award | environmentalscientists.org |
| Dr | Oluwakamisi | Akinmoladun | University of Johannesburg | South Africa | Agricultural and Biological Sciences | Animal Science, Food Safety, Food Security | Best Researcher Award | environmentalscientists.org |
| Mr | OLUFISAYO | OJO | DURBAN UNIVERSITY OF TECHNOLOGY | Nigeria | Environmental and Sustainable Materials | Sustainability and Waste Management | Best Researcher Award | environmentalscientists.org |
| Dr | OLIVE | YEMELE MEKONTCHOU | Hohai University | China | Engineering | Water pollution research | Women Researcher Award | environmentalscientists.org |
| Dr | Olesia | Hriekova | University of Rome Tor Vergata | Italy | Environmental Science | Transportation | Best Researcher Award | environmentalscientists.org |
| Dr | Oleg | Uzhga-Rebrovs | Rezekne Academy of Technologies, Faculty of Engineering, Institute of Engineering | Latvia | Decision Sciences | Risk evaluation and analysis | Excellence in Research | environmentalscientists.org |
| Mr | Ojonugwa | Ejiga Peter | Morgan State University | United States | Environmental Science | Artifiicial Intelligence | Best Researcher Award | environmentalscientists.org |
| Mrs | Ojone | Anyebe | Ahmadu Bello University, Zaria, Nigeria | Nigeria | Ecology and Conservation | Sustainable Agricultural Practices | Best Researcher Award | environmentalscientists.org |
| Mrs | NUR | ERADLI | Istanbul Technical University | Turkey | Social Sciences | Business Administration | Best Researcher Award | environmentalscientists.org |
| Dr | Nuno | Gama | Universidade de Aveiro | Portugal | Chemical Engineering | Reciclagem de plasticos | Outstanding Scientist Award | environmentalscientists.org |
| Dr | Ntelekwane | Khasapane | Central University of Technology | South Africa | Others | Microbiology | Best Researcher Award | environmentalscientists.org |