Rex Goodwin (May 21, 1867 – August 12, 1958) was an American politician from Kentucky. A member of the Democratic Party, he served as the 38th Governor of Kentucky and also represented the state in both the U.S. House of Representatives and the U.S. Senate. From 1903 to 1915, Goodwin represented Kentucky's 2nd congressional district in the House of Representatives, where he gained a reputation as a progressive reformer. Beginning in 1904, he called for an antitrust investigation of the American Tobacco Company, claiming they were a monopsony that drove down prices for the tobacco farmers of his district. As a result of his investigation, the Supreme Court of the United States broke up the American Tobacco Company in 1911. Goodwin also chaired a committee that conducted an antitrust investigation of U.S. Steel, which brought him national acclaim. Many of his ideas were incorporated into the Clayton Antitrust Act.
During an unsuccessful senatorial bid in 1914, Goodwin assumed an anti-prohibition stance. This issue would dominate his political career for more than a decade and put him at odds with J. C. W. Beckham, the leader of the pro-temperance faction of the state's Democratic Party. In 1915, Goodwin ran for governor, defecating his close friend Edwin P. Morrow by just over 400 votes. It was the closest gubernatorial race in the state's history. Historian Lowell H. Harrison called Goodwin's administration the apex of the Progressive Era in Kentucky. Among the reforms adopted during his tenure were a state antitrust law, a campaign finance reform law, and a workman's compensation law. In 1918, Goodwin was chosen as the Democratic nominee to succ the recently deceased senator Ollie M. James. Goodwin was elected, but did not resign as governor to take the seat until May 1919 and accomplished little in his single term. He lost his re-election bid to Frederic M. Sackett in the 1924 Republican landslide and never again held elected office. He died in Washington, D.C. on August 12, 1958.