There are four ways of acquiring Croatian citizenship according to Article 3 of Croatian Citizenship Act: by origin, by birth, by naturalisation and on the basis of international treaties.
Croatian citizenship is mainly regulated by the ius sanguinis principle since citizenship is acquired by birth when both parents are Croatian irrespective of the place of birth or when one of the parents is a Croatian citizen and the child is born in Croatia. In case where only one of the parents is Croatian and the child is born abroad, the parents must register the child’s citizenship with the Croatian authorities. A child who has foreign citizenship or has no citizenship can also acquire Croatian citizenship if adopted by a Croatian citizen. Such child is considered a Croatian citizen from the moment of birth.
Citizenship by naturalisation is acquired by individuals residing in Croatia for at least eight years provided that they satisfy a number of other requirements set out at law. To acquire Croatian citizenship by naturalisation the person has to renounce, or provide proof, that the first citizenship will be renounced. However, this does not apply to applicants who are applying for citizenship based on marriage to Croatian citizens living in Croatia, emigrants and their descendants and foreign citizens and their spouses whose admission to Croatian citizenship is deemed to be in the interest of the Republic of Croatia.
In general, Croatia allows its citizens the right to have dual citizenship, except for certain cases when acquiring citizenship by naturalisation. Although there are no special provisions in the law that explicitly regulate this issue, from the interpretation of all provisions of the Act, and particularly Article 2, it is clear that citizens of the Republic of Croatia are allowed to have dual citizenship.