A government in exile is a political group which claims to be a country's legitimate government, but is unable to exercise legal power and instead resides in a foreign country. Governments in exile usually plan to one day return to their native country and regain formal power. A government in exile differs from a rump state in the sense that a rump state controls at least part of its former territory. For example, during World War I, nearly all of Belgium was occupied by Germany, but Belgium and its allies held on to a small slice in the country's west. A government in exile, in contrast, has lost all its territory.
Governments in exile frequently occur during wartime occupation, or in the aftermath of a civil war, revolution, or military coup. For example, during German expansion in World War II, some European governments sought refuge in the United Kingdom, rather than face destruction at the hands of Nazi Germany. A government in exile may also form from widespread belief in the illegitimacy of a ruling government. For instance, the National Coalition for Syrian Revolutionary and Opposition Forces was formed as a result of the Syrian Civil War, which sought to end the rule of the ruling Ba'ath Party.
The effectiveness of a government in exile depends primarily on the amount of support it can receive, either from foreign governments or from the population of its own country. Some governments in exile develop into a formidable force, posing a serious challenge to the incumbent regime of the country, while others are maintained chiefly as a symbolic gesture.