- ONERA - The French Aerospace Lab [Châtillon]
- ONERA - The French Aerospace Lab [Lille]
- ONERA - The French Aerospace Lab [Palaiseau]
- ONERA [Modane]
- ONERA | DEMR, Université de Toulouse [Toulouse]
- ONERA, Université Paris Saclay [Palaiseau]
- Observatoire Volcanologique du Piton de la Fournaise
- Observatoire aquitain des sciences de l'univers
- Observatoire de la Côte d'Azur
- Obstetrics and Gynecology Unit,
- Oceans and Atmosphere
- Oklahoma Medical Research Foundation
- Oncogenesis, Stress, Signaling
- Oncologie virale
- Ontario Institute for Cancer Research [Canada]
- Optical Sciences Division,
- Optimisation thérapeutique en Neuropsychopharmacologie
- Optoelectronics Research Center
- Optoelectronics Research Centre
- Orange Labs R&D [Rennes]
- Orange Labs [Chatillon]
- Orange Labs [La Turbie]
- Organisation Nucléaire et Oncogenèse | Nuclear Organization and Oncogenesis
- Osaka Bioscience Institute
- Oxford Astrophysics