The Twenty-third Amendment of the Constitution Act 2001 of the Constitution of Ireland is an amendment that permitted the state to become a party to the International Criminal Court (ICC). It was approved by referendum on 7 June 2001 and signed into law on the 27 March 2002. The referendum was held on the same day as referendums on the prohibition of the death penalty, which was also approved, and on the ratification of the Nice Treaty, which was rejected.