The House of Habsburg-Lorraine originated from the marriage in 1736 of Francis III, Duke of Lorraine and Bar, and Maria Theresa of Austria, later successively Queen of Bohemia, Queen of Hungary, Queen of Croatia and Archduchess of Austria. Its members are the legitimate surviving line of both the House of Habsburg and the House of Lorraine and inherit their patrimonial possessions from their female line of the House of Habsburg and from the male line of the House of Lorraine.

Francis I was Holy Roman Emperor, Archduke of Austria, Duke of Lorraine and Bar, and Grand Duke of Tuscany. He became the ruler of the Holy Roman Empire of the German Nation, Austria, and Tuscany through his marriage to Maria Theresa, daughter of Emperor Charles VI. Francis was the last non-Habsburg monarch of the Empire. The couple were the founders of the Habsburg-Lorraine dynasty, and their marriage produced sixteen children.