- Hampton University
- Hanscom Air Force Base
- Hansen Experimental Physics Lab [Stanford]
- Harvard John A. Paulson School of Engineering and Applied Sciences
- Harvard-Smithsonian Center for Astrophysics
- Harvard University
- HELIOS - LATMOS
- Helmholtz-Gemeinschaft = Helmholtz Association
- Helmholtz-Zentrum Geesthacht
- Helsingin yliopisto = Helsingfors universitet = University of Helsinki
- Helsinki Observatory
- Hermanus Magnetic Observatory
- Hessischer Rundfunk
- High Altitude Observatory
- Hokkaido University [Sapporo, Japan]
- Hovemere Ltd.
- Howard University
- Hughes STX Corporation [Greenbelt]
- Hungarian Academy of Sciences
- Huygens Laboratory
- HydroMeteorological Service of the Emilia-Romagna Regional Agency for Environmental Protection
- Hydrosciences Montpellier