The siege of Kőszeg or siege of Güns in the Kingdom of Hungary within the Habsburg Empire, that took place in 1532. In the siege, the defending forces of the Austrian Habsburg monarchy under the leadership of Croatian Captain Nikola Jurišić, defended the small border fort of Kőszeg with only 700–800 Croatian soldiers, with no cannons and few guns. The defenders prevented the advance of the Ottoman army of over 100,000 toward Vienna, under the leadership of Sultan Suleiman the Magnificent and Pargalı Ibrahim Pasha.

Most scholars agree that the defending Christian Knights Emerged victorious over the Ottoman invaders. Suleiman, having been delayed nearly four weeks, withdrew at the arrival of the August rains, and did not continue towards Vienna as he had intended, but turned homeward.

Suleiman secured his possession in Hungary by conquering several other forts, but after the Ottoman withdrawal, Habsburg Emperor Ferdinand I reoccupied some of the devastated territory. Following this, Suleiman and Ferdinand concluded a 1533 treaty of Constantinople that confirmed the right of John Zápolya as a king of all Hungary, but recognised Ferdinand's possession of some of the reoccupied territory.