Karl Ludwig, Archduke of Austria (30 July 1833 - 19 May 1896) was the father of Franz Ferdinand of Austria, whose shooting occasioned the start of World War I.

He was born at Schönbrunn in Vienna, the son of Franz Karl Josef of Austria (1802-1878) and his wife Sophie Fredericka of Bavaria (1805-1872). His elder brothers were the Emperor Franz Joseph of Austria and Archduke Maximilian, who became Emperor of Mexico.

He married three times. His first wife, whom he married on 11 April 1856 at Dresden, was Margaretha Carolina Friederike Cecile Auguste Amalie Josephine Elisabeth Maria Johanne Princess of Saxony Duchess of Saxony (1840-1858), the daughter of Johann of Saxony (1801-1873) and his wife Amelia of Bavaria (1801-1877). She died on 15 September 1858: they had no children.

His second wife, whom he married by proxy on 16 October 1862 at Rome, and in person on 21 October 1862 at Venice, was Maria Annunciata of Bourbon-Sicily (1843-1871), daughter of Fernando II of the Two Sicilies (1810-1859) and his wife Maria Teresa of Austria (1816-1867).

They had four children:

• Franz Ferdinand of Austria (1863-1914)
• Otto Franz of Austria (1865-1906)
• Ferdinand Karl of Austria
• Margarete Sophie of Austria (1870-1902)

Maria Annunciata died on 4 May 1871.

His third wife, whom he married on 23 July 1873 at Kleinheubach, was Donha Maria Teresa da Imaculada Conceicão Fernanda Eulália Leopoldina Adelaida Isabel Carolina Micaela Rafaela Gabriela Francisca de Asis e de Paula Gonzaga Inès Sofia Bartolomea des Anjons, Infanta of Portugal (1855-1944), daughter of King Miguel I of Portugal and his wife Adelaide Sophie Prinzessin zu Löwenstein-Wertheim-Rosenberg.

They had two daughters,

• Maria Annunziata of Austria
• Elisabeth Amalie of Austria (1878-1960)

Karl Ludwig died of typhoid at Schönbrunn in Vienna. His widow, Maria Teresa died 12 February 1944.