Floyd E. Thompson (December 25, 1887 – October 18, 1960) was a justice of the Supreme Court of Illinois and a criminal lawyer who defended American businessman Samuel Insull in 1934 against mail fraud and antitrust charges.

In November 1912, he won election as State's attorney for Rock Island County, Illinois.

In 1919, a vacancy arose on the Supreme Court of Illinois when Justice George A. Cooke stepped down to become chief counsel of Peoples Gas Light and Coke Company, and Thompson ran for this seat, winning election in April 1919.

He lost to Louis Lincoln Emmerson as part of the landslide 1928 victory of Herbert Hoover and the Republicans.

During his time at the firm, Thompson served as lead counsel in what was arguably the most sensational prosecution of the Great Depression era, that of Samuel Insull, the president of Commonwealth Edison, whose share price had collapsed in 1929, wiping out the life savings of thousands of small investors.