Marie-Luise "Marlies" Horn (15 March 1912 – 26 July 1991) was a German tennis player who was active in the 1930s.
In mixed doubles, she reached the final alongside Roland Journu in 1937 where they were defeated by Mathieu and Yvon Petra.
[5] In 1937, Horn went on a world tour together with the best German male players Gottfried von Cramm, Henner Henkel and coach Heinrich Kleinschroth which led them to the United States and Japan.
[8] In doubles, she teamed with Anita Lizana; they were defeated in the quarterfinals by Sarah Palfrey and Alice Marble.
[10] After their stay at Japan, the men continued their trip towards Australia, and Horn returned to Germany from Manila.