Formal or informal associations of human beings, usually in pursuit of some common goal
- California, Libertarian Party of
- Canada, Libertarian Party of
- Cascade Policy Institute - Non-profit research and educational organization that focuses on Oregon
- Casey Youth Conference on Liberty and Entrepreneurship - Conference sponsored by ISIL, Casey Research and Lobo Tiggre
- Cato Institute - Non-profit public policy research foundation in Washington, DC
- Center for Independent Thought - Non-profit educational foundation based in New York City
- Centro de Divulgacion del Conocimiento Economico - CEDICE, Venezuela
- Centro de Estudios de la Realidad Economica y Social - CERES, Uruguay
- Chicago, Libertarian Party of - Illinois
- Circle Bastiat - Informal group of friends of Murray Rothbard in the early 1950s, named after the nineteenth century French economist
- Club for Growth - Helps elect candidates who support limited government and lower taxes
- Cognitive Liberty and Ethics, Center for - Fosters intellectual freedom and cognitive liberty
- Colleges and Universities
- Colorado, Libertarian Party of
- Competitive Enterprise Institute - Dedicated to the principles of free enterprise and limited government
- Conferences - Conferences, conventions and other periodic meetings
- Connecticut, Libertarian Party of
- Convention, 2004 Libertarian National - May 27-31, 2004 - Atlanta, GA