The Siege of Vienna in 1529 was the first attempt by the Ottoman Empire, led by Suleiman the Magnificent, to capture the city of Vienna, Austria. The siege came in the aftermath of the 1526 Battle of Mohács, which had resulted in the death of the King of Hungary and the descent of the kingdom into civil war, with rival factions supporting the Habsburg Archduke Ferdinand I of Austria and others supporting the Ottoman backed John Zápolya. The Ottoman attack on Vienna was part of their intervention into the Hungarian conflict, intended in the short term to secure Zápolya's position. Historians disagree in their interpretation of Ottoman long-term goals and regarding what motivations lay behind the choice of Vienna in particular as the target of the campaign. The failure of the siege marked the beginning of 150 years of bitter military tension and reciprocal attacks, culminating in a second siege of Vienna in 1683.

There is speculation by some historians[5] that Suleiman's main objective in 1529 was actually to assert Ottoman control over the whole of Hungary, the western part of which (known as Royal Hungary) was under Habsburg control. The decision to attack Vienna after such a long interval in Suleiman's European campaign is viewed as an opportunistic manoeuvre after his decisive victory in Hungary. Other scholars[5] theorise that the suppression of Hungary simply marked the prologue to a later, premeditated invasion of Europe.[5]