- J. Heyrovský Institute of Physical Chemistry of the ASCR
- JIFRESSE
- JRC Institute for Environment and Sustainability
- James Franck Institute
- Janelia Farm Research Campus
- Jet Propulsion Laboratory
- Jeunes Équipes de l'Institut de Physique du Collège de France
- Jodrell Bank Centre for Astrophysics
- Johann Radon Institute for Computational and Applied Mathematics
- Johann-Friedrich Blumenbach Institut für Zoologie und Anthropologie
- Johnson Matthey Technology Centre