Frederic R. DeYoung (September 12, 1875 – November 16, 1934) was an American jurist and politician who served as a judge on the Supreme Court of Illinois (1924–1934), judge on the Superior Court of Cook County (1923–1924), judge on the original Circuit Court of Cook County (1921), member of the Illinois House of Representatives (1915–1919), and the city attorney of Harvey, Illinois (1908–1919), among other public offices. DeYoung ran as a Republican for most of his political career. However, in his last campaign (his 1933 reelection to the Supreme Court of Illinois), he ran instead as a Democrat.