The military history of Bhutan begins with the Battle of Five Lamas in 1634, marking Bhutan's emergence as a nation under the secular and religious leadership of Zhabdrung Ngawang Namgyal. Before Bhutan emerged as a separate nation, it remained on the periphery of Tibetan military and political influence. The region that became Bhutan was host to several battles and waves of refugees from turmoil in Tibet. After its founding, Bhutan was invaded numerous times by outside forces, namely Tibetans, Mongols, and the British. Bhutan meanwhile invaded its traditional tributaries in Sikkim, Cooch Behar, and the Duars.
Bhutan effectively ceased all international military hostilities in 1865 under the Treaty of Sinchula after its defeat by the British Empire. Under the terms of the subsequent Treaty of Punakha in 1910, Bhutan effectively became a British protectorate. Bhutan has maintained this status with India under Bhutan–India relations since 1949 and has modernly engaged only in limited domestic operations against Indian separatist groups.