William Hartman Woodin (May 27, 1868 – May 3, 1934) was a U.S. industrialist. He served as the Secretary of Treasury under Franklin Roosevelt in 1933.
Woodin was born in Berwick, Pennsylvania. He was closely involved in Jackson and Woodin Manufacturing Company. His father, Clemuel Ricketts "Clement" Woodin, preceded him in the presidency of the company and his grandfather, also named William Hartman Woodin, was an early partner in the company. He was a member of the Union League Club of New York. Woodin graduated from Columbia College School of Mines in 1890.
Jackson & Woodin grew under this combined leadership to become the largest railroad car builder in the eastern United States, and was one of the 13 companies that merged in 1899 to form American Car and Foundry Company (ACF).
Woodin married Annie Jessup, on October 9, 1889. They had three daughters and one son: Mary, Annie Jessup, William Hartman, Jr., and Elizabeth Foster Woodin. They lived in New York City.