Princess Marie of Windisch-Graetz (11 December 1856 – 9 August 1929) was an Austrian noblewoman and a noted archaeologist.

In Schwerin on 5 May 1881, she married her first cousin, the German-born Duke Paul Frederick of Mecklenburg-Schwerin, second son of Frederick Francis II, Grand Duke of Mecklenburg-Schwerin, and his wife, Princess Augusta Reuss of Köstritz.

[2] The couple had three surviving children, all of whom were raised as Roman Catholics, Marie's religion,[3] and lived a quiet life in Venice, where they befriended Cardinal Sarto (later Pope Pius X), who often visited the family and acted as their spiritual advisor.

[2][5] In 1887 her husband, raised a Lutheran, converted to Roman Catholicism, the religion of his wife and their common children.

Some of the artifacts were sold to museums in Harvard, Oxford and Berlin by her daughter Duchess Marie Antoinette of Mecklenburg.