William Simon U’Ren (January 10, 1859 – March 5, 1949) was an American lawyer and political activist. U’Ren promoted and helped pass a corrupt practices act, the presidential primary, and direct election of U.S. senators. As a progressive activist, U’Ren championed the initiative, referendum, and recall systems in an effort to bring about a Georgist “Single Tax” on the unimproved value of land, but these measures were also designed to promote democracy and weaken the power of backstage elites. His reforms in Oregon were widely copied in other states. He supported numerous other reforms, such as the interactive model of proportional representation, which was not enacted.