- Pacific Northwest National Laboratory
- Pacific University
- Paderborn University
- Panasonic Corporation
- Paris Brain Institute
- Paris Observatory
- Paris-Saclay University
- Particle
- Partnership for Clean Competition
- Pasteur Institute
- Paul Scherrer Institute
- PeerJ
- Peking University
- Penn State College of Engineering
- Penn State Eberly College of Science
- Pennsylvania State University
- Pensoft Publishers
- Peoples' Friendship University of Russia
- Perelman School of Medicine at the University of Pennsylvania
- Perimeter Institute for Theoretical Physics
- Peter MacCallum Cancer Centre
- Physics Institute, Heidelberg University
- Physikalisch-Technische Bundesanstalt
- Pittsburgh Supercomputing Center
- Planetary Science Institute
- PlanetEarth Online
- Plataforma SINC
- Plymouth Marine Laboratory
- Pohang University of Science and Technology
- Polish Academy of Sciences
- Polytechnic University of Catalonia
- Polytechnic University of Milan
- Polytechnich Institute of New York City
- Polytechnique Montréal
- Pompeu Fabra University
- Portland State University
- Potsdam Institute for Climate Impact Research
- Princess Margaret Hospital
- Princess Máxima Center for Pediatric Oncology
- Princeton Plasma Physics Laboratory
- Princeton University
- Public Library of Science
- Publicase Comunicação Científica
- Purdue University
- Pusan National University