| acu.ac.uk | Association of Commonwealth Universities (ACU) |
| commonwealth-planners.org | Commonwealth Association of Planners |
| cbcglobelink.org | Commonwealth Business Council |
| cba.org.uk | Commonwealth Broadcasting Association |
| cata-tax.org | Commonwealth Association of Tax Administrators |
| casle.org | Commonwealth Association of Surveying and Land Economy (CASLE) |
| capgan.org | Commonwealth Association of Paediatric Gastroenterology and Nutrition |
| comnet.mt | Commonwealth Association for Public Administration and Management |
| acarm.org | Association of Commonwealth Archivists and Records Managers |
| thecommonwealth.org | The Commonwealth Secretatiat |