Joan Menzies (born 1907) was a British woman who served as a typist for the Foreign and Commonwealth Office during the 1930s. The niece of MI6 chief Stewart Menzies, she was assigned to assist the civil servant Hugh Legat in spying on the Nazis during the Munich Conference of 1938. She managed to conceal a document smuggled to Legat by the German diplomat Paul von Hartmann, preventing the SS officer Franz Sauer from locating it; however, the document was rendered useless by the conclusion of the Agreement, as the document - revealing Hitler's expansionist designs in Central Europe - would have dissuaded Prime Minister Neville Chamberlain from making peace with the Germans and facilitated an anti-Nazi military coup in Germany.