Princess Katharina Alexandra Dorothea von Lieven, née Freiin von Benckendorff, 17 December 1785 – 27 January 1857), was a Baltic German noblewoman and the wife of Prince Christoph Heinrich von Lieven, who served as the Russian ambassador to London between 1812 and 1834. She became an influential figure among many of the diplomatic, political, and social circles of 19th-century Europe.

Baltic German nobility was a privileged social class in the territories of today's Estonia and Latvia. It has existed continuously since the Northern Crusades and the medieval foundation of Terra Mariana. Most of the nobility were Baltic Germans, but with the changing political landscape over the centuries, Polish, Swedish and Russian families also became part of the nobility, just as Baltic German families re-settled in locations such as the Swedish and Russian Empires. The nobility of Lithuania is for historical, social and ethnic reasons separated from the German-dominated nobility of Estonia and Latvia.