The Emergency Powers Act 1939 (EPA) was an Act of the Oireachtas enacted on 3 September 1939, after an official state of emergency had been declared on 2 September 1939 in response to the outbreak of the Second World War. The Act empowered the government to:make provisions for securing the public safety and the preservation of the state in time of war and, in particular, to make provision for the maintenance of public order and for the provision and control of supplies and services essential to the life of the community, and to provide for divers and other matters connected with the matters aforesaid.

The policy of neutrality was adopted by Ireland's Oireachtas at the instigation of the Taoiseach Éamon de Valera upon the outbreak of World War II in Europe. It was maintained throughout the conflict, in spite of several German air raids by aircraft that missed their intended British targets, and attacks on Ireland's shipping fleet by Allies and Axis alike. Possibilities of both German and British invasions were discussed in the Dáil. Both eventualities were prepared for, although most detailed preparations were done with the Allies under Plan W. De Valera's ruling party, Fianna Fáil, supported his neutral policy for the duration of the war.