Archduchess Mechthildis of Austria (11 October 1891 – 6 February 1966) was a daughter of Archduke Charles Stephen of Austria and a first cousin of King Alphonso XIII of Spain.
She was a member of the Teschen branch of the House of Habsburg-Lorraine and an Archduchess of Austria and Princess of Hungary, and Bohemia by birth.
In 1913 she married Prince Olgierd Czartoryski.
The couple had four children and lived in Poland until the outbreak of World War II when they emigrated to Brazil.