19 of 2001) was a proposed amendment to the Constitution of Ireland to allow the state to ratify the Treaty of Nice of the European Union.

Under the decision of the Supreme Court in Crotty v. An Taoiseach (1987), an amendment to the Constitution was required before it could be ratified by Ireland.

The Twenty-fourth Amendment was proposed in Dáil Éireann by Minister for Foreign Affairs Brian Cowen on behalf of the Fianna Fáil–Progressive Democrats coalition government led by Taoiseach Bertie Ahern.

[3] It passed final stages in the Dáil on 2 May, with insufficient opposition to force a roll call vote.

Because of concerns that the Treaty would affect Irish neutrality, a further subsection was included on that occasion to address these fears.