Anna Leopoldovna (
än'nə lyā'əpôl'dəvnə) or
Anna Karlovna (
kär'ləvnə), 1718-46, duchess of Brunswick-Wolfenbüttel, regent of Russia (1740-41); daughter of Charles Leopold, duke of Mecklenburg-Schwerin, and of Catherine, sister of Czarina Anna of Russia. She married the prince of Brunswick-Wolfenbüttel, and their son,
Ivan VI, succeeded (1740) Anna as czar. After the deposition of Ivan by Czarina
Elizabeth, Anna Leopoldovna and her husband were imprisoned. She died in childbirth.