The Indo-Pakistani War of 1965, also known as the Second India–Pakistan War, unfolded over several stages, marked by key events and strategic shifts. The conflict originated from the longstanding dispute over Jammu and Kashmir. It escalated following Pakistan's Operation Gibraltar in August 1965,^[40] designed to infiltrate forces into Jammu and Kashmir to precipitate an insurgency against Indian rule.^[41] The operation's discovery led to increased military tensions between the two countries.

The war saw significant military engagements, including the largest tank battle since World War II. Both India and Pakistan utilized their land, air, and naval forces. Notable operations during the war included Pakistan's Operation Desert Hawk and India's counter-offensive on the Lahore front. The Battle of Asal Uttar was a critical point where Indian forces inflicted heavy losses on Pakistan's armored division. Pakistan's air force performed effectively despite being outnumbered, particularly in defending Lahore and other strategic locations.

The war culminated in September 1965 with a ceasefire, following diplomatic intervention by the Soviet Union and the United States and the adoption of United Nations Security Council Resolution 211. The Tashkent Declaration subsequently formalized the ceasefire. By the end of the conflict, India held a larger area of Pakistani territory, mainly in fertile regions like Sialkot, Lahore, and Kashmir, while Pakistan's gains were primarily in desert regions opposite Sindh and near the Chumb sector in Kashmir.

The war led to significant geopolitical shifts in the subcontinent, with both India and Pakistan feeling a sense of betrayal by the lack of support from their previous allies, the United States and the United Kingdom. This shift resulted in India and Pakistan developing closer relationships with the Soviet Union and China, respectively. The conflict also had profound effects on the military strategies and foreign policies of both nations.

In India, the war is often perceived as a strategic victory, leading to changes in military strategy, intelligence gathering, and foreign policy, particularly a closer relationship with the Soviet Union. In Pakistan, the war is remembered for the performance of its air force and is commemorated as Defence Day. However, it also led to critical evaluations of military planning and political outcomes, as well as economic strains and increased tensions in East Pakistan. The war's narrative and its commemoration have been subjects of debate within Pakistan.