National defense is a nation's use of military, economic and political power to maintain survival.

National defense or national defence may also refer to:

  • National Defense (Poland), a volunteer military formation of the Second Polish Republic
  • National Defense (magazine), a business and technology magazine published by the National Defense Industrial Association
  • National missile defense, a military strategy to shield a country from missiles
  • Movement of National Defence, a Greek government during WWI

See also

  • Ministry of defence, part of a government responsible for matters of defence
  • National security (disambiguation)
  • Defense (disambiguation)
  • National Defence Academy (disambiguation)
  • National Defence University (disambiguation)