Isolationism may refer to:
- Generally to foreign policies that range from military neutrality to nearly complete diplomatic and commercial isolation.
- Specifically to American Foreign Policy Isolationism
One of history's most famous examples of nearly complete isolation is the sakoko or "closed country" policy adopted by the Tokugawa Shogunate in Japan from the seventeenth to nineteenth centuries, when almost all external communications and trade were banned, excluding some strictly limited trade with the Chinese and Dutch. Note that the Japanese never used the term "isolationism" to describe their withdrawal from the world. This came to an end in the 1850s, with the arrival of American naval ships in Japanese harbours, negotiating an end to Japanese isolation more or less by force and precipitating social upheavals which included rapid industrialisation, the fall of the Shogunate, the restoration of the Emperor, and an era of much more aggressive nationalism.
In modern times, such complete isolationism is not practical, since any country which chose to ignore international politics and sever communications completely would leave itself extremely vulnerable. However, there are still some countries which try to remain as "closed" as possible to the outside world. Examples include China during the early part of the Cold War, and North Korea.