The Slav tribes, mixed with Illyrians, Avars and Romans, formed the semi-independent dukedom of Duklja by the 10th century. In 1077, Pope Gregory VII recognized Duklja as an independent state, acknowledging its King Mihailo (Michael) (of the Vojislavljevic dynasty founded by nobleman Stefan Vojislav) as rex Docleae (King of Duklja). The kingdom, however, paid tribute to the Byzantine Empire; later to the Bulgarian Empire; it gave birth to the later medieval kingdom of the Serbian Grand Prince (Serbian: župan) Stefan Nemanja, who originated from Duklja.

Duklja in the 10th century

The Principality of Zeta (which more closely corresponds to the early modern state of Montenegro) asserted itself towards 1360. The House of Balšic (1360s–1421) and the House of Crnojevic (1421–1499) ruled Zeta; and though the Ottoman Empire controlled the lands to the south and east from the 15th century, it never fully conquered Zeta.

In 1516, the secular prince Ðurad Crnojevic abdicated in favour of the Archbishop Vavil, who then made Montenegro into a theocratic state under the rule of the prince-bishop (vladika) of Cetinje, a position held from 1697 by the Petrovic-Njegoš family of the Ridani clan. Petar Petrovic Njegoš, perhaps the most influential vladika, reigned in the first half of the 19th century. In 1851 Danilo II Petrovic Njegoš became vladika, but in 1852 he married, left the priesthood, assumed the title of knjaz (Prince), and transformed his land into a secular principality.

In 1910, Prince Nikola I became King of Montenegro. Two years later, in October, 1912, King Nikola declared war on the Ottoman Empire, precipitating the two Balkan Wars. The Montenegrin army attacked the Ottoman fortress city of Skutari, and forced the empire to gather a large army in neighboring Macedonia. This Ottoman army was then attacked by the forces of Greece, Serbia, and Bulgaria which entered the war by pre-arrangement. The result was a military disaster for the Ottomans, who were thrown back to an area north of Constantinople.

Montenegro emerged from the Balkan Wars doubled in size, receiving half of the former Ottoman territory known as the Sanjak of Novi Pazar, but without Skutari, the country's major prize in the war. The London Conference awarded Skutari to an independent Albania.

An allied power during World War I, Montenegro was occupied by Austro-Hungarian troops. Feldmarschalleutnant Viktor Weber von Webenau became Military Governor of Montenegro on February 26, 1916. In 1918, the Podgorica Assembly voted for uniting Montenegro with the Kingdom of Serbia. However, pro-independence Montenegrins revolted on Christmas Day 1919 against Serbia. The revolt was finally suppressed in 1924.

From 1919 to 1941, Montenegro was a part of the Kingdom of Serbs, Croats and Slovenes, which renamed itself the Kingdom of Yugoslavia in 1929. During World War II, Montenegro was occupied by Italian troops and later German Axis troops (1941–1944). From 1945 to 1992, Montenegro separated from Serbia and became a constituent republic in its own right of the Socialist Federal Republic of Yugoslavia. It was during this time that the present capital Podgorica was renamed Titograd, after Josip Broz Tito, leader of Yugoslavia. Over the next half century, Montenegro remained one of six constituent republics of Yugoslavia.