- Oak Ridge National Laboratory [Oak Ridge]
- Oakland University
- Obafemi Awolowo University
- Oberthur Technologies
- Objets communicants pour l'Internet du futur
- Observatoire technologique
- Observatório do Valongo|UFRJ [Rio de Janeiro]
- Ochadai Academic Production
- Ochanomizu University
- Océ-Technologies B.V.
- Okan University
- Okayama University
- Okayama University of Science
- Oklahoma State University [Stillwater]
- Old Dog Consulting Ltd
- Old Dominion University [Norfolk]
- Omnitor AB
- OneSource, Consultoria Informática Lda. [Coimbra]
- Open Universiteit Nederland [Heerlen]
- Open University of Cyprus
- Open University of Israël
- Open University of the Netherlands [Heerlen]
- Opole University of Technology
- Orange Communications SA
- Orange Labs
- Orange Labs R&D [Rennes]
- Orange Labs [Caen]
- Orange Labs [Chatillon]
- Orange Labs [Issy les Moulineaux]
- Orange Labs [Lannion]
- Orange Labs [Meylan]
- Orange Labs [Paris]
- Orange Labs [Sophia Antipolis]
- Orange Polska
- Oregon State University
- Organisation for Economic Co-operation and Development
- Osaka Electro-Communication University
- Osaka Prefecture University
- Osaka University
- Osaka University [Osaka]
- Oslo Metropolitan University
- Oslo University College
- Oslo and Akershus University College of Applied Sciences [Oslo]
- Osnabrück University of Applied Sciences
- Ostravská univerzita | University of Ostrava
- Ostwestfalen-Lippe University of Applied Sciences
- Otani University [Kyoto]
- Otto-von-Guericke-Universität Magdeburg = Otto-von-Guericke University [Magdeburg]
- Oulu University of Applied Sciences
- OutSystems
- Oxford Brookes University
- Oxford Immune Algorithmics
- Oxford University Computing Laboratory
- Oxford e-Research Centre [Oxford]
- Örebro School of Public Affairs
- Örebro University
- Örebro University School of Business