2005 Luxembourg European Constitution referendum

A referendum on ratifying the proposed European Constitution was held in Luxembourg on 10 July 2005. The referendum was Luxembourg's first since 1937. On 28 June 2005 Parliament approved the constitution in advance of the referendum, and although the referendum was consultative, parliament agreed to abide by the results.

Prime Minister Jean-Claude Juncker said that he expected a close vote and that he would resign if the referendum resulted in a 'no' vote. The final opinion poll published a month before the referendum indicated a small advantage for the "yes", but with 16% of voters undecided. Luxembourg is traditionally regarded as one of the EU's most enthusiastic member states, and most prominent political figures support the Constitution, with both the governing coalition and the main opposition parties campaigning for a 'yes' vote.

The proposal was approved by 56% of voters, making Luxembourg was the thirteenth EU member state to approve the EU treaty, but only the second approved in a referendum (after Spain). The vote came after French and the Dutch voters rejected the EU treaty.