[2] The Treaty entered into force on 1 July 2013, making Croatia the 28th country to join the European Union.

Croatia submitted its application to join the European Union on 21 February 2003, became an official candidate on 18 June 2004, and started accession negotiations on 3 October 2005.

The treaty was signed on 9 December 2011 in Brussels and entered into force on 1 July 2013, having been ratified by Croatia and the European Union's 27 member states.

The document does not include a monitoring mechanism of Croatia by the European Commission to ensure continued reform, as was the case with Bulgaria and Romania.

[89] In February 2013, representatives of all major parties in Slovenia agreed to approve Croatia's accession after experts and foreign ministers from both countries reached a compromise deal.