- XanTec Bioanalytics [Muenster]
- XaRTA
- Xavier University
- XEGEN, 15 rue de la République, 13420, Gémenos
- Xelect Ltd, Scottish Oceans Institute
- xénobiotiques
- Xénobiotiques
- Xeno-canto foundation
- Xenothera [Nantes, France]
- XenTech
- Xeolas Pharmaceuticals Ltd
- XeriusTracking SARL
- XGCIFAL PONTEVEDRA ESP
- Xiamen University
- Xiamen University Malaysia
- Xiangnan University,
- Xiangtan University
- Xi'an Institute of Optics and Precision Mechanics
- Xi’an Jiaotong-Liverpool University
- Xi'an Jiaotong-Liverpool University [Suzhou]
- Xi'an Jiaotong University
- Xi'an Polytechnic University
- Xi’an University of Arts and Science
- Xi'an University of Arts and Science (CHINA)
- Xiao Dong Pro-health (Suzhou) Instrumentation Co Ltd
- Xidian University
- Xilema
- Xilema Control Biológico
- Xinhua Hospital
- Xinjiang Acad Agr Sci
- Xinjiang Acad Agr Sci, Inst Hort, Urumqi, Peoples R China
- Xinjiang Academy of Agricultural and Reclamation Sciences
- Xinjiang Academy of Agricultural Sciences
- Xinjiang Academy of Animal Science
- Xinjiang Agricultural University
- Xinjiang Agricultural University [Ürümqi]
- Xinjiang Astronomical Observatory
- Xinjiang Institute of Ecology and Geography
- Xinjiang Institute of Ecology and Geography [Urumqi]
- Xinjiang Medical University
- Xinjiang University
- Xinxiang Medical University
- Xishuangbanna Station for Tropical Rain Forest Ecosystem Studies
- Xishuangbanna Tropical Botanical Garden
- XLIM
- XMM-Newton Science Operations Centre
- XOC editorial
- XOC Estudio
- XOMA (U.S.)
- x-OvO Limited
- XP-MED
- X'Press : diffraction et hautes pressions
- X-ray Science Division
- XR-Repro
- XR Reprod
- Xsira Pharmaceuticals Inc.
- Xtnt
- XtreeE [Rungis, France]
- XTU Architects
- Xuanwu Hospital of Capital
- Xurian Environnement
- Xuzhou Medical College