Margret Elizabeth Rey (May 10, 1906 – December 21, 1996), born Margarete Elisabeth Waldstein, was (with her husband H. A. Rey), the co-author and illustrator of children's books, the most famous of which are the Curious George series.

Margarete Waldstein was born in Hamburg in 1906; her father was a member of the Reichstag. She studied art at Bauhaus in Dessau, Kunstakademie Düsseldorf, and the University of Munich, and afterwards worked in advertising. In 1935, she left Germany for Rio de Janeiro, Brazil to escape Nazism. While there, she met her future husband Hans (who was a salesman and also from Hamburg). They married in 1935 and moved to Paris, France, in 1936. [2]