Isidor Srul Fisch (26 July 1905 – 29 March 1934) was a German friend and business associate of Bruno Hauptmann, from whom Hauptmann claimed to have received a box containing gold certificates; those certificates were part of the ransom money in the kidnapping of Charles Augustus Lindbergh, Jr.
The Fisch story was an integral part of Hauptmann's unsuccessful defense in his kidnapping and murder trial.