The Montenegrin Army contained about 40,000 men in 1914. Most of Montenegro's 15,000 square kilometres was mountainous. As Montenegro had been fighting to maintain its independence from Turkey for many years, its soldiers were experienced guerrilla fighters.

On the outbreak of the First World War, Montenegro joined the Triple Entente against the Triple Alliance. The army fought with the Serbian Army against Austro-Hungary on the Eastern Front in 1914.

Montenegro was overrun by the Central Powers during the last months of 1915. The army surrendered in January 1916 but some escaped and joined the Serbian Army. These forces helped to recapture Montenegro during the autumn of 1918.