The Constitution of Croatia in its preamble defines Croatia as a nation state of ethnic Croats, a country of traditionally present communities that the constitution recognizes as national minorities and a country of all its citizens. National minorities explicitly enumerated and recognized in the Constitution are Serbs, Czechs, Slovaks, Italians, Hungarians, Jews, Germans, Austrians, Ukrainians, Rusyns, Bosniaks, Slovenes, Montenegrins, Macedonians, Russians, Bulgarians, Poles, Romani, Romanians, Istro-Romanians ("Vlachs"), Turks and Albanians. Article 12 of the constitution states that the official language in Croatia is Croatian, but also states that in some local governments another language and Cyrillic or some other script can be introduced in official use.
The official use of minority languages is defined by relevant national legislation and international conventions and agreements which Croatia signed. The most important national laws are Constitutional Act on the Rights of National Minorities, Law on Use of Languages and Scripts of National Minorities and Law on Education in Language and Script of National Minorities. Relevant international agreements are European Charter for Regional or Minority Languages and Framework Convention for the Protection of National Minorities. Certain rights were achieved through bilateral agreements and international agreements such as Treaty of Osimo and Erdut Agreement.