The Concert of Nations sanctioned the creation of Belgium in 1830 on the condition that the country remain strictly neutral. During the two World Wars Belgium tried, but was unable, to follow a policy of neutrality due to the German invasions. In 1948, Belgium signed the Treaty of Brussels with Great Britain, France, the Netherlands, and Luxembourg, and a year later became one of the founding members of NATO.

Belgium remains a strong proponent of both NATO and European defense efforts. Belgium also is a strong advocate of strengthening economic and political integration within the EU. Having federalized their own country, many Belgians view themselves as the ultimate "European federalists."

Both NATO (since 1966) and the EU have their headquarters in Brussels; SHAPE (Supreme Headquarters Allied Powers Europe) is in the south of the country, near Mons.

Belgium actively supports the expansion of NATO and EU membership to the new democracies of central and eastern Europe and is actively engaged in the Organization for Security and Cooperation in Europe.