The Battle of Vienna in 1683 (as distinct from the Siege of Vienna in 1529), marked the final turning point in a 250-year struggle between the forces of Christian Europe and the Islamic Ottoman Empire. Over the 16 years following the battle Christian forces would permanently drive the Turks south of the Danube River, where they never again posed a serious threat to central Europe.

The battle, which took place on September 12, 1683, pitted a large Austrian and German army of about 100,000 troops and their allies, a 30,000-man relief force under Jan III Sobieski, King of the Polish-Lithuanian Commonwealth, against their Turkish besiegers. The Turks, commanded by Pasha Kara Mustafa, numbered approximately 140,000 men, although a large portion of them played no part in the battle.

Before the siege, the Viennese had demolished many of the houses around the city walls and cleared the debris, leaving an empty plain that would expose the Turks to defensive fire if they tried to rush the city. Kara Mustafa solved that problem by ordering his forces to dig long lines of trenches directly towards the city to help protect them from the defenders as they advanced towards it. A goal of this digging was to decrease the stability of the walls around Vienna. Additionally, the Ottoman siege cut virtually every means of food supply into Vienna, and the population started to starve. (For example, the Viennese cavalry had to start killing their own horses for food. After the later dispersal of the Turks, the Polish army reported many horse thefts.)

Sobieski began planning a relief expedition to Vienna during the summer of 1683, when the hard-pressed Turks launched an all-out offensive against Austria. The Ottomans and Austria had clashed repeatedly for more than 150 years, and Mustafa planned an expedition to put a final end to this situation. Starting in March, the Turks moved toward the city, and finally invested it on July 14. The previous winter, Austria and Poland had concluded a treaty in which the Austrian Emperor would support Sobieski if the Turks attacked Kraków; in return, the Poles would support Austria if Vienna came under attack.

The Polish king honored his obligations to the letter, going so far as to leave his own nation virtually undefended. He covered this with a stern warning to Imre Thököly, the leader of Hungary (then an Ottoman satellite), whom he threatened with destruction if he tried to take advantage of the situation.

Mustafa's men had managed to take part of the walls of Vienna by exploding mines under them, but he inexplicably did not make dispositions to defend against Sobieski even after learning of his arrival. At 4 in the morning on September 12, the Austrian army on the left and the German forces in the center moved forward against the Turks. Mustafa launched a counterattack with most of his force. Then the Polish infantry launched a massive assault on the right flank. After 12 hours of fighting, Sobieski's men held the high ground on the right.

At about 5 in the afternoon, four cavalry groups, one of them German-Austrian and the other three composed of Polish heavy cavalry (Husaria), 20,000 men in all, led by the Polish king, charged down the hills. In the confusion, they made straight for the Ottoman camps, while the Vienna garrison sallied out of its defenses and joined in the assault. In less than three hours, the Christians won the battle, as the Turks beat a hasty retreat to the south and east. Although no one realized it at the time, that day shaped the outcome of the entire war as well. The Ottomans fought on for another 16 years before giving up, losing vast territories in the process.

The Turks lost about 15,000 men in the fighting, compared to approximately 4,000 for the allied Christian forces.