Karl Gengler (8 October 1886 – 9 October 1974) was a German politician of the Christian Democratic Union (CDU) and former member of the German Bundestag.
From the first election until 1957 he was a member of the German Bundestag. He won the direct mandate in the Rottweil constituency in both 1949 and 1953. In the Bundestag he was deputy chairman of the Committee on Rules of Procedure and Immunity.