Montenegro–Serbia relations

Montenegro and Serbia maintain diplomatic relations established in 1879. Both were part of the Kingdom of Yugoslavia (1918–1941) and later the Socialist Federal Republic of Yugoslavia (1945–1992). After Yugoslavia’s dissolution in 1991-1992, they formed the Federal Republic of Yugoslavia which was in 2003 reconstituted into the State Union of Serbia and Montenegro. The Montenegrin independence referendum in 2006, resulting in restoration of both countries' independence, marked a political divergence, but cultural ties between Serbia and Montenegro remain exceptionally strong.

The two countries have a deep historical and cultural connection, rooted in the centuries of intertwined history. The peoples of Serbia and Montenegro share common cultural traditions, including religion (majority in both countries adhere to the Serbian Orthodox Church) and language (vast majority in Serbia and relative majority in Montenegro speak Serbian as a mother tongue). About two million people in Serbia have partial or full ancestry from present-day Montenegro, mostly tracing back to the 18th and 19th centuries, vast majority of whom identify ethnically as Serb, though many (particularly first- or second-generation descendants from Montenegro) also claim a fairly strong Montenegrin regional identity. This closeness between Serbia and Montenegro causes sporadic debates on the Montenegrin ethnic and linguistic identity centering on a core question whether Montenegrins are essentially the same people as Serbs or distinct ethnicity.