Formal or informal associations of human beings, usually in pursuit of some common goal
- Mackinac Center for Public Policy - Promotes sound solutions to state and local policy questions in Michigan
- Maine, Libertarian Party of
- Manhattan Libertarian Party - New York
- Marijuana Policy Project - American lobbying organization, works to minimize harm associated with marijuana
- Maryland, Libertarian Party of
- Massachusetts, Libertarian Party of
- Miami-Dade County, Libertarian Party of - Florida
- Michigan, Libertarian Party of
- Minnesota, Libertarian Party of
- Mises Institute - Research and education in classical liberalism, libertarian political theory, and Austrian School of economics
- Mississippi, Libertarian Party of
- Missouri Libertarian Party
- MIT Libertarians - Massachusetts Institute of Technology
- Monroe Libertarians - Florida
- Montana Libertarian Party
- Mont Pelerin Society - Aims to strengthen the principles and practice of a free society
- Movimiento Libertario - Libertarian party in Costa Rica