National defense (disambiguation)

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