The Franco-Ottoman Alliance, also known as the Franco-Turkish Alliance, was an alliance established in 1536 between the King of France Francis I and the Sultan of the Ottoman Empire Suleiman I. The strategic and sometimes tactical alliance was one of the most important foreign alliances of France, and was particularly influential during the Italian Wars. The Franco-Ottoman military alliance reached its peak around 1553 during the reign Henry II of France.
The alliance was exceptional, as the first non-ideological alliance in effect between a Christian and Muslim state, and caused a scandal in the Christian world. Carl Jacob Burckhardt (1947) called it "the sacrilegious union of the lily and the crescent". It lasted intermittently for more than two and a half centuries, until the Napoleonic campaign in Ottoman Egypt, in 1798–1801.