Clarence Lieder (August 15, 1906 – January 1969) was a mechanic and armorer for Chicago's underworld and Depression-era criminals, as well as the primary competitor to Joe Bergl. Owner of the Oakley Auto Construction Company, located at the corner of Division Street and Oakley Avenue in Chicago's North Side, Lieder competed with Bergl in supplying both mobster and other criminals with customized automobiles throughout Prohibition and during the early-1930s.