The League of Nations was an international organization founded after the First World War at the Paris Peace Conference in 1919. The League's goals included disarmament; preventing war through collective security; settling disputes between countries through negotiation and diplomacy; and improving global welfare.

Under the diplomatic philosophy, the League was a government of governments, with the role of settling disputes between individual nations in an open and legalist forum. The impetus for the founding of the League came from U.S. President Woodrow Wilson, but, along with many other countries, the United States never joined the League of Nations.

The League lacked an armed force of its own and so depended on the Great Powers to enforce its resolutions, which they were often very reluctant to do. After a number of notable successes and some early failures, the League ultimately proved incapable of preventing aggression by the fascist Axis Powers in the 1930s. The onset of the Second World War made it clear that the League had failed in its primary purpose - to avoid any future world war. The United Nations effectively replaced it after World War II and inherited a number of agencies and organizations founded by the League.

In contrary to United Nations Organization which issues own stamps, the League of Nations used overprinted Swiss stamps.