Ottoman Hungary was the southern and central parts of what had been the Kingdom of Hungary in the late medieval period, and which were conquered and ruled by the Ottoman Empire from 1541 to 1699. The Ottoman rule covered almost the entire region of the Great Hungarian Plain (except the northeastern parts) and Southern Transdanubia.

The territory was invaded and annexed to the Ottoman Empire by Sultan Suleiman the Magnificent between 1521 and 1541. The north-western rim of the Hungarian kingdom remained unconquered and recognised members of the House of Habsburg as Kings of Hungary, giving it the name "Royal Hungary". The boundary between the two thereupon became the frontline in the Ottoman–Habsburg wars over the next 150 years. Following the defeat of the Ottomans in the Great Turkish War, most of Ottoman Hungary was ceded to the Habsburgs under the Treaty of Karlowitz in 1699.

During the period of Ottoman rule, Hungary was divided for administrative purposes into Eyalets (provinces), which were further divided into Sanjaks. Ownership of much of the land was distributed to Ottoman soldiers and officials with about 20% of the territory being retained by the Ottoman state. As a border territory, much of Ottoman Hungary was heavily fortified with troop garrisons. Remaining economically under-developed, it became a drain on Ottoman resources. Although there was some immigration from other parts of the Empire and some conversions to Islam, the territory remained largely Christian. The Ottomans were relatively religiously tolerant and this toleration allowed Protestantism to prosper unlike in Royal Hungary where the Habsburgs repressed it. By the end of the 16th century, around 90% of the population was Protestant, mainly Calvinist.

In these times, the territory of present-day Hungary began to undergo changes due to the Ottoman occupation. Vast lands remained unpopulated and covered with woods. Flood plains became marshes. The life of the inhabitants on the Ottoman side was unsafe. Peasants fled to the woods and marshes, forming guerrilla bands, known as the Hajdú troops. Eventually, the territory of present-day Hungary became a drain on the Ottoman Empire, swallowing much of its revenue into the maintenance of a long chain of border forts. However, some parts of the economy flourished. In the huge unpopulated areas, townships bred cattle that were herded to south Germany and northern Italy - in some years they exported 500,000 head of cattle. Wine was traded to the Czech lands, Austria and Poland.