- Jackson School of Geosciences
- Jacobs University = Constructor University [Bremen]
- James Cook University
- Japan Aerospace Exploration Agency
- Japan Aerospace Exploration Agency [Sagamihara]
- Japan Agency for Marine-Earth Science and Technology
- Japan Meteorol Agcy, Meteorol Res Inst, Tsukuba, Ibaraki, Japan
- Japan Meteorological Agency
- JASCO Applied Sciences
- Jenderal Soedirman University [Purwokerto, Indonesia]
- Jeonbuk National University
- Jet Propulsion Laboratory
- Jilin University
- Jinan University [Guangzhou]
- Johannesburg University
- Johannes Gutenberg - Universität Mainz = Johannes Gutenberg University
- Johann Heinrich von Thünen-Institut = Thünen Institute
- Johns Hopkins University
- Join Research Centre
- Joint Clinical Research Centre
- Joint Global Change Research Institute
- Joint Institute for Marine and Atmospheric Research
- Joint Institute for the Study of the Atmosphere and Ocean
- Joint Institute for the Study of the Atmosphere and Oceans
- Joint Program on the Science and Policy of Global Change
- Joint Research Centre of the European Commission
- Jomo Kenyatta University of Agriculture and Technology
- JRC Institute for Environment and Sustainability
- Justus-Liebig-Universität Gießen = Justus Liebig University