| Conflict: | Hungarian campaign of Suleiman |
| Partof: | the Ottoman–Habsburg wars Habsburg–Ottoman war of 1529–1533 |
| Date: | 1529 |
| Place: | Hungary |
| Result: | Ottoman victory |
| Territory: | Ottomans re-occupy Győr, Komárom, Esztergom, and Buda |
| Combatant1: | Habsburg Austria Holy Roman Empire Kingdom of Bohemia Kingdom of Croatia Ferdinand's Hungarian kingdom |
| Combatant2: | Ottoman Empire Moldavia John Szapolyai's Hungarian kingdom |
| Commander1: | Ferdinand I |
| Commander2: | Suleiman the Magnificent Pargalı Ibrahim Pasha John Szapolyai Peter IV Rareș |
| Strength1: | Unknown |
| Strength2: | 120,000 soldiers[1] (including 12,000 Janissaries) 20,000 camels 300 guns 6,000 Hungarian horsemen |
| Casualties1: | 20,000 dead (soldiers and civilians) |
| Casualties2: | 40,000 dead |
Suleiman I's campaign of 1529 was launched by the Ottoman Empire to take the Austrian capital Vienna and thereby strike a decisive blow, allowing the Ottomans to consolidate their hold on Hungary. This was in response to Ferdinand I's daring assault on Ottoman Hungary.
Suleiman's march to Vienna was also an attempt to assist his vassal, John Szapolyai who claimed the throne of Hungary. Suleiman sent his army of 120,000 strong north on the 10 May 1529. His campaign was marked by speedy success, on September 8 Buda surrendered to the Ottomans and John Szapolyai was installed as King of Hungary. Suleiman then went further taking Esztergom, Tata, Komárom and Győr[1] so that much of Ferdinand I's gains the previous two years were lost. On 27 September, Suleiman reached Vienna.
The arrival of the Sultan's massive host in Central Europe caused much panic across Europe - Martin Luther, who had believed that the Ottomans were God's punishment against the sins of Christians[2] modified his views and wrote the book the War with the Turks in 1529 urging that "the scourge of God" should be fought with great vigour. However, when Suleiman began besieging Vienna it would prove to be his first and most decisive blunder.