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.

A state of emergency is a situation in which a government is empowered to put through policies that it would normally not be permitted to do, for the safety and protection of its citizens. A government can declare such a state during a natural disaster, civil unrest, armed conflict, medical pandemic or epidemic or other biosecurity risk.