During the 2nd World War, Ireland (at that time officially known as Eire), along with Sweden, Switzerland, Spain, and Portugal, was neutral. During the 1st World War (1914-1918) before Irish independence was achieved (1921), the British enforced conscription in Ireland even when the vast majority of the Irish people were clearly not only against English rule, but against Irish involvement in what they viewed as a "conflict between colonial super powers".

All in all the Irish suffered more soldier casualties than any other British country (England, Scotland or Wales) during the war, which only gave more credence to the accusations that the British were using Irish troops as "cannon fodder" and needlessly sending the Irish off to die. By the time the 2nd World War began most of the Irish people, including Ireland's Prime Minister, Eamon de Valera, though sympathizing with the Allied cause against Nazi Germany, could not enter into an alliance with the United Kingdom. Ireland had fought a war to regain her independence and human rights from the British from 1919-1921 (the Anglo-Irish War) in which thousands had died, so memories still remained from British conscription during World War 1, and the atrocities committed by the "Black and Tans" (British paramilitary police) who were sent to quell the rebels and civilian support for the rebels during the Anglo-Irish War.

Also Eire (now called the Republic of Ireland or Phoblacht na Eire in Irish) and the United Kingdom were still (and still are) disputing jurisdiction over the six counties of Northern Ireland. Although Eire stayed neutral, the Irish government still helped the Allied cause, by providing aid to the people of Belfast during the German air raids on the city. In response Germany broke their neutrality agreement and bombed a working class district in Dublin.

The Irish Republican Army (not the same army which had fought against the British during the Anglo-Irish War, but its radical splinter group which kept the name) worked with Nazi Germany against the British. The U.K. remained in possession of Northern Ireland, and the IRA was beginning what would become a struggle to reunite Ireland, the IRA worked with Nazi spies, while the government of Eire shared any information it had about the Axis with the governments of the U.K. and the U.S. So during the 1930s, both Allied and Axis spies were working in Ireland.

Today unlike Sweden, Switzerland and Japan, Ireland is not officially a neutral country and could join any war it pleases. Although the Irish have not been involved in an actual "war" since their independence war against Britain (1919-1921) and the subsequent civil war that broke out in the independent state between moderates and radicals (1922-1923), the Irish Republic has been a leader in peace-keeping and peace-making missions around the world, much like Canada.