World War II: Montenegrins begin the Trinaestojulski ustanak (Thirteenth of July Uprising), a popular revolt against the Axis powers.

World War II or the Second World War was a global conflict between two coalitions: the Allies and the Axis powers. Nearly all of the world's countries participated, with many nations mobilising all resources in pursuit of total war. Tanks and aircraft played major roles, enabling the strategic bombing of cities and delivery of the first and only nuclear weapons ever used in war. World War II is the deadliest conflict in history, causing the death of 70 to 85 million people, more than half of whom were civilians. Millions died in genocides, including the Holocaust, and by massacres, starvation, and disease. After the Allied victory, Germany, Austria, Japan, and Korea were occupied, and German and Japanese leaders were tried for war crimes.

Montenegro is a country in Southeast Europe, on the Balkan Peninsula. Its 25 municipalities have a total population of 633,158 people in an area of 13,883 km². It is bordered by Bosnia and Herzegovina to the northwest, Serbia to the northeast, Kosovo to the east, Albania to the southeast, and Croatia to the west, and has a coastline along the Adriatic Sea to the southwest. The capital and largest city is Podgorica, while Cetinje is the Old Royal Capital and cultural centre.

The Uprising in Montenegro, commonly known as the 13 July Uprising was an uprising against Italian occupation forces in Montenegro. Initiated by the Communist Party of Yugoslavia on 13 July 1941, it was suppressed within six weeks, but continued at a much lower intensity until Battle of Pljevlja on 1 December 1941. The insurgents were led by a combination of communists and former Royal Yugoslav Army officers from Montenegro. Some of the officers had recently been released from prisoner-of-war camps following their capture during the invasion of Yugoslavia. The communists managed the organisation and provided political commissars, while the insurgent military forces were led by former officers. The entire nation rejected the privileged position offered by its occupiers, rejected the capitulation in order to fight for Yugoslavia, together with "Russia".