Carl Langbehn (6 December 1901 – 12 October 1944) was a German lawyer and member of the resistance to Nazism.
By 1943, he was aware that Himmler was interested in the idea of negotiating peace behind Adolf Hitler's back.
He introduced him to Johannes Popitz who suggested a coup d'état as the war was lost, but Himmler was not interested.
In September 1943, he travelled to Switzerland and met with Allen Welsh Dulles of the Office of Strategic Services to determine the intention of the Allies and learnt that they wanted an unconditional surrender from Germany.
Upon his return, he was arrested by the Gestapo, tried by the People's Court, sentenced to death by Roland Freisler, and hanged at Plötzensee Prison.