- Jack Baskin School of Engineering
- Jacobs Technology ESCG
- Jacobs University = Constructor University [Bremen]
- JADBio Gnosis DA S.A., Science and Technology Park of Crete, Heraklion,
- JAIST - Ishikawa - Japon
- Jakarta Islamic State University
- James Cook University
- James Watt School of Engineering [Univ Glasgow]
- Janssen Research & Development
- Japan Advanced Institute of Science and Technology
- Japan Aerospace Exploration Agency [Sagamihara]
- Japan Aerospace Exploration Agency [Tokyo]
- Japan Aerospace Exploration Agency [Tsukuba]
- Japan Agency for Marine-Earth Science and Technology
- Japan Atomic Energy Agency
- Japan Meteorological Agency
- Japan Synchrotron Radiation Research Institute [Hyogo]
- Jawaharlal Nehru University
- Jaypee University of Engineering and Technology
- Jaypee University of Information Technology
- JDSU Uniphase
- Jefferson (Philadelphia University + Thomas Jefferson University)
- Jeju National University
- Jena University Hospital [Jena]
- Jeremiah Horrocks Institute for Mathematics, Physics and Astronomy [Preston]
- Jet Propulsion Laboratory
- JEUMONT Electric
- JEUMONTELECTRIC
- Jeumont Electric, Altawest
- JEUMONT ELETRIC
- Jeunes Équipes de l'Institut de Physique du Collège de France
- J. Gutenberg-University
- J. Heyrovský Institute of Physical Chemistry of the ASCR
- Jiangxi Normal University
- Jilin Normal University
- Jodrell Bank Centre for Astrophysics
- Johannes Gutenberg - Universität Mainz = Johannes Gutenberg University
- Johannes Kepler Universität
- John Innes Centre [Norwich]
- John P. Hussman Institute for Human Genomics
- Johns Hopkins University
- Johns Hopkins University Applied Physics Laboratory [Laurel, MD]
- Johns Hopkins University School of Medicine [Baltimore]
- Joint ALMA Observatory
- Joint ALMA Observatory, Santiago
- Joint ALMA Office
- Joint Astronomy Centre
- Joint Attosecond Science Laboratory
- Joint Centre for Hydro-Meteorological Research, Met Office Hadley Centre
- Joint Institute for High Temperatures of the RAS
- Joint Institute for Laboratory Astrophysics
- Joint Institute for VLBI in Europe
- Joint Japanese-French Robotics Research Laboratory [Japon]
- Jordan University of Science and Technology [Irbid, Jordan]
- Joseph Louis LAGRANGE
- Josip Juraj Strossmayer University of Osijek
- Jozef Stefan Institute [Ljubljana]
- JRC Institute for Environment and Sustainability
- JRC Institute for Transuranium Elements [Karlsruhe]
- J. Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia
- Jülich Centre for Neutron Science
- Jülich Centre for Neutron Science (JCNS), Forschungszentrum Jülich GmbH at Heinz Maier-Leibnitz Zentrum (MLZ)
- Jülich Research Centre
- Jülich Supercomputing Centre
- Julius-Maximilians-Universität Würzburg = University of Würzburg
- JUNIA
- Justus-Liebig-Universität Gießen = Justus Liebig University
- J.W. Goethe-Universität