Archduke Rainer of Austria was a member of the House of Habsburg-Lorraine, a member of the Tuscan branch of the Imperial House of Habsburg, an Archduke of Austria and Prince of Tuscany by birth. He was the eldest son Archduke Leopold Salvator of Austria, Prince of Tuscany. He served as officer in the Austrian army during World War I. At the fall of the Habsburg dynasty, he remained in Vienna and worked for a time as taxi driver. He died unmarried at the age of 34 from blood-poisoning.

Archduke Leopold Salvator, Prince of Tuscany, was the son of Archduke Karl Salvator of Austria and Princess Maria Immaculata of Bourbon-Two Sicilies.