Encyclopedias, Almanacs, Transcripts, and Maps
- Multimember District
- Multinational Corporations, Global Markets, and the Constitution
- Mundt-Nixon Bill (1948–1949)
- Municipal Bankruptcy Act 48 Stat. 798 (1934)
- Municipal Immunity
- Murdock v. Pennsylvania 319 U.S. 105 (1943)
- Murphy v. Florida 421 U.S. 794 (1975)
- Murphy v. Ford 390 F. Supp. 1372 (1975)
- Murphy, Frank (1890–1949)
- Murphy, Paul L. (1923–1997)
- Murray's Lessee v. Hoboken Land & Improvement Company 18 Howard 272 (1856)
- Murray, William (Lord Mansfield) (1705–1793)
- Muskrat v. United States 219 U.S. 346 (1911)
- Napoleonic Wars, Espionage During
- National Command Authority
- National Drug Threat Assessment
- National Information Infrastructure Protection Act, United States
- National Intelligence Estimate
- National Interagency Civil-Military Institute (NICI), United States
- National Liberation Army (ELN)—Colombia