Language is much more than a simple tool of communication; it is an essential element of group identity. Nations, ethnic groups, cultures are hardly imaginable without a common language. In a multiethnic country by choosing one “official language” the state in many respects favours the users of that language and discriminates those citizens whose mother tongue is different from the official language. The real and demanding issue is how to obey the principles of the rule of law in the case of the official language in a multiethnic state. Serbia, and its uniquely multiethnic Vojvodina province, has a rich and developed legislation concerning official language use, including the official language use of minorities. Although, the Constitution and actual legislation render the Serb language as the primary official language of the country, minority languages could be officially used as well in areas inhabited by minority populations. Notwithstanding the existing shortcomings of the relevant legislation, the principle of the rule of law is violated much more by the actual practice and poor implementation of relevant legal provisions. Fact and figures prove that many language rights are not implemented because of a lack of human resources, executive activities and financial and organisational measures for implementation. In order to make substantial progress in the field of implementation of minority language rights it is necessary both to modify and harmonise the relevant legislation and also to put into effect organisational, executive and financial measures which can make the rules a living practice. It is also important to differentiate between various minority languages and various individual situations and to take into account the actual needs of minorities, the possibilities of the administration and so-called acquired language rights.