The Indo-Pakistani war of 1965, also known as the second India–Pakistan war, was an armed conflict between Pakistan and India that took place from August 1965 to September 1965. The conflict began following Pakistan's Operation Gibraltar, which was designed to infiltrate forces into Jammu and Kashmir to precipitate an insurgency against Indian rule. The seventeen-week war caused thousands of casualties on both sides and witnessed the largest engagement of armored vehicles and the largest tank battle since World War II. Hostilities between the two countries ended after a ceasefire was declared through UNSC Resolution 211 following a diplomatic intervention by the Soviet Union and the United States, and the subsequent issuance of the Tashkent Declaration. Much of the war was fought by the countries' land forces in Kashmir and along the border between India and Pakistan. This war saw the largest amassing of troops in Kashmir since the Partition of India in 1947, a number that was overshadowed only during the 2001–2002 military standoff between India and Pakistan. Most of the battles were fought by opposing infantry and armored units, with substantial backing from air forces, and naval operations.

Operation Gibraltar was the codename of a military operation planned and executed by the Pakistan Army in the territory of Jammu and Kashmir, India in August 1965. The operation's strategy was to covertly cross the Line of Control (LoC) and incite the Muslim-majority Kashmiri population's uprising against the Indian Government. The military leadership believed that a rebellion by the local Kashmiri population against Indian authorities would serve as Pakistan's casus belli against India on the international stage.