Citizenship in Montenegro is regulated by the Montenegrin Citizenship Law of 2008, and it is based on the principle of ius sanguinis. Montenegrin citizenship can be acquired either by origin, birth in certain cases, naturalisation or international agreements and treaties.
In general, dual citizenship is not allowed in Montenegro. According to article 8.2 of the Montenegrin Citizenship Law, the renunciation of previous citizenship is a mandatory requirement, unless a bilateral treaty states otherwise. However, there are a few exceptions to this rule.
One of the exceptions refers to citizens who were the holders of dual citizenship before Montenegro declared independence on 3rd June 2006.
In addition, an exception is made for those who acquired citizenship by naturalisation pursuant to the criteria pertaining to the Special Program of Investments of Special Significance for Commercial and Economic Montenegrin Interest, which took effect on 1st January 2019. The law prescribes the conditions upon which an applicant can acquire naturalisation in exchange for a financial contribution. Article 16 of the Decision prescribes that, in the period of duration of the programme no more than 2000 applicants can acquire citizenship with this special program. To qualify for the Special Programme, applicants must make a non-refundable government contribution of €100,000 and invest in development projects approved by the Government. The latter may include an investment of either €250,000 in development projects in under-developed regions of Montenegro, or €450,000 in development projects in developed regions of Montenegro.
Other than these exceptions, according to Article 24 of the Montenegrin Citizenship Law, the consequences of non-registration and non-renunciation of a second citizenship amount to the loss of citizenship of Montenegro. This is an ex lege procedure in Montenegro.