- ATOS Origin
- ATOS [madrid]
- Aalborg University [Denmark]
- Aalto University
- Abdelmalek Essaadi University [Tétouan] = Université Abdelmalek Essaadi [Tétouan]
- Accademia Musicale Studio Musica
- Adani Institute of Infrastructure Engineering
- Aditro [Espoo]
- Agios Therissos Medical Diagnostic Centre
- Agricultural University [Plovdiv]
- AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement
- Ain Shams University
- Aix Marseille Université
- Alexander Technological Educational Institute of Thessaloniki
- Algorithms for the Grid
- Alma Mater Studiorum Università di Bologna = University of Bologna
- Altice Labs [Aveiro]
- American University of Beirut [Beyrouth]
- Anglia Ruskin University
- Animal Health Research Institute
- Animal Health and Veterinary Laboratories Agency
- Applied informatics in management and economy [Messolonghi]
- Approches Littéraires, Linguistiques et Historiques des Sources
- Archéologie et Archéométrie
- Aristotle University of Thessaloniki
- Arizona State University [Tempe]
- Artificial Intelligence Lab, Faculty of Computer Science
- Artificial Intelligence Research Institute | Spanish Scientific Research Council
- Arts et Métiers ParisTech
- Arts et Métiers Sciences et Technologies
- Association EURATOM-CEA
- Associazione Euratom-ENEA sulla Fusione
- AstraZeneca
- Ateneo de Manila University
- Athens Technology Center S.A. [Athènes]
- Athens University of Economics and Business
- Athinoula A. Martinos Center for Biomedical Imaging
- Athonet
- Atilim University
- Atos Spain
- Auckland University of Technology
- Automated Scheduling, Optimisation and Planning Research Group, School of Computer Science
- Avid Radiopharmaceuticals
- Avlos
- Axon logic
- “Attikon” University Hospital