Members with the Letter O
- O'Brien, Paul -- United Kingdom -- University of Manchester
- O'Connor, Glenda -- United States -- U.S. Department of Energy
- O'Connor, Cyril -- South Africa -- University of Cape Town
- O'Donohue, Stephen -- United Kingdom -- Polymer Laboratories, Ltd.
- O'Driscoll, K. -- Canada
- O'Ferrall, Rory -- Ireland -- National University of Ireland
- O'Hare, Patrick -- United States
- O'Keeffe, Michael -- United States -- Arizona State University
- O'Melia, C. -- United States -- The Johns Hopkins University
- Ober, Christopher -- United States -- Cornell University
- Odetti, Héctor -- Argentina -- Universidad Nacional del Litoral
- Oehrlein, Gottlieb -- United States -- University of Maryland
- Oelgemöller, Michael -- Ireland -- Dublin City University
- Ogawa, Keiichiro -- Japan -- University of Tokyo
- Ogino, Hiroshi -- Japan
- Ogude, Nthabiseng -- South Africa -- University of Pretoria
- Ohno, Kohji -- Japan -- Kyoto University
- Ohno, Atsuyoshi -- Japan
- Ohrström, Lars -- Sweden -- Chalmers University of Technology
- Ohta, Teruto -- Japan -- Chemical Society of Japan
- Ohtaki, Hitoshi -- Japan
- Oivanen, Mikko -- Finland -- University of Helsinki
- Oka, Masahito -- Japan -- Osaka Prefecture University
- Okamoto, Kensaku -- Japan
- Oki, Michinori -- Japan
- Olaj, O. -- Austria -- University of Vienna
- Oleinik, Eduard -- Russia -- Russian Academy of Sciences
- Olesen, Henrik -- Denmark
- Oliveira, Márcia -- Brazil -- National Institute of Technology (INT)
- Oliveira Brett, Ana Maria -- Portugal -- Universidade de Coimbra