A referendum on the EU accession of the Republic of Croatia was held on 22 January 2012. Croatia finished accession (membership) negotiations on 30 June 2011 and signed the Treaty of Accession on 9 December 2011, setting it on course to become the bloc's 28th member state. The Constitution of Croatia requires that a binding referendum be held on any political union reducing national sovereignty, such as via European Union membership. On 23 December 2011 the Croatian Parliament made a preliminary decision on EU accession and determined that the referendum would be held on 22 January 2012. The 2012 Croatian EU accession referendum was the first referendum held in Croatia since the Croatian independence referendum held more than 20 years earlier, in 1991.

The foreign relations of Croatia is primarily formulated and executed via its government which guides the state's interactions with other nations, their citizens, and foreign organizations. Active in global affairs since the 9th century, modern Croatian diplomacy is considered to have formed following their independence from Yugoslavia in 1991. As an independent state, Croatia established diplomatic relations with most world nations – 187 states in total – during the 1990s, starting with Germany (1991) and ending most recently with Togo (2023). Croatia has friendly relations with most of its neighboring countries, namely Slovenia, Hungary, Montenegro, and Italy. They maintain colder, more tense relations with Serbia as well as Bosnia and Herzegovina due to historic nation-building conflict and differing political ideologies.