Luiz (Ludwig) Heinrich Mann (27 March 1871 – 11 March 1950) was a German novelist and the elder brother of Nobel Prize winning author Thomas Mann. He wrote works with strong social themes, and his numerous criticisms of the growth of fascism forced him to flee for his life after the Nazis came to power in 1933.

Mann's essay on Emile Zola and the novel Der Untertan (translated under the titles Man of Straw and The Loyal Subject) earned him much respect during the Weimar Republic, since it satirized German society and explained how its political system had led to the First World War. Eventually, his book Professor Unrat was freely adapted into the legendary movie Der Blaue Engel (The Blue Angel). Carl Zuckmayer wrote the script, and Josef von Sternberg was the director. The book's author wanted his girlfriend, the actress Trude Hesterberg, to play the lead, but instead Marlene Dietrich was given her first sound role as the "actress" Lola Lola (named Rosa Fröhlich in the novel).

Mann became persona non grata in Nazi Germany and left even before the Reichstag fire in 1933. He went to France where he lived in Paris and Nice. During the German occupation he made his way to Marseille in Vichy France and there was aided by Varian Fry in 1940 to escape to Spain. He then went to Portugal and eventually to America, where he lived until his death.