Citizenship in Montenegro is regulated by the Montenegrin Nationality 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 and international agreements and treaties.
As a general rule, dual Citizenship is not allowed in Montenegro. According to Article 8 point 2, of the Montenegrin Citizenship Law, the renunciation of previous citizenship is a mandatory requirement. Furthermore, this fact is confirmed by Article 18, of the same Citizenship Law, where it is stipulated that dual citizenship is allowed in very limited circumstances, more accurately when a bilateral contract is signed and accepted between the countries.
An exception is enunciated in Article 12 of the Law, which implies that dual citizenship is allowed for those who attain citizenship through the Montenegro Citizenship by Investment Programme.
One other exception exists for citizens who held dual nationality before Montenegro declared independence on 3 June 2006. However those acquiring dual citizenship after 3 June 2006, may keep their dual citizenship only with countries that have signed a bilateral agreement with Montenegro, on the condition of reciprocity. At present only Macedonia has signed such a bilateral agreement.
According to Article 24 of the Montenegrin Citizenship Law, the consequences of non-registration and non-renunciation of a second citizenship is the loss of citizenship of Montenegro. This is an ex lege procedure in Montenegro.