Thomas Updegraff (April 3, 1834 – October 4, 1910) was an American attorney, politician, and five-term Republican member of the U.S. House of Representatives from northeastern Iowa.

Thomas Updegraff, a descendant of the Dutch[1] and German Op den Graeff family, was born in Tioga County, Pennsylvania.

Through Abrahams father Herman Updegraff (1711-1758) and grandfather Isaac Updegraff (1680-1745) they were direct descendants of Abraham op den Graeff (father of Isaac), one of the founders of Germantown and in 1688 signer of the first protest against slavery in colonial America and of his grandfather Herman op den Graeff, mennonite leader of Krefeld.

In 1892, he again ran for Congress in Iowa's 4th district, winning not only the Republican nomination but also the general election (where he defeated incumbent Democrat Walter Halben Butler).

However, in 1898, he was defeated in his bid for the Republican nomination by Gilbert N. Haugen, who would go on to serve seventeen consecutive terms.