Franz Ferdinand (18 December 1863 – 28 June 1914) was an Archduke of Austria-Este, Austro-Hungarian and Royal Prince of Hungary and of Bohemia, and from 1889 until his death, heir presumptive to the Austro-Hungarian throne. His assassination in Sarajevo precipitated Austria-Hungary's declaration of war against Serbia. This caused the Central Powers (including Germany and Austria-Hungary) and the Allies of World War I (countries allied with Serbia) to declare war on each other, starting World War I.

He was born in Graz, Austria, the eldest son of Archduke Karl Ludwig of Austria (younger brother of Franz Joseph and Maximilian) and of his second wife, Princess Maria Annunciata of Bourbon-Two Sicilies. When he was only twelve years old, his cousin Duke Francis V of Modena died, naming Franz Ferdinand his heir on condition that he add the name Este to his own. Franz Ferdinand thus became one of the wealthiest men in Austria.