Ira Francis Marion Butler (May 20, 1812 – January 16, 1909) was an American politician who served in the Oregon Territorial House of Representatives and the Oregon House of Representatives as a member of the Democratic Party. He served as Speaker of the Oregon House of Representatives from 1857 to 1858, which was the last session before Oregon's statehood. Before immigrating to Oregon, Butler served as sheriff of Warren County, Illinois, and was circuit court clerk for Stephen A. Douglas when he was an Illinois judge. After moving to Oregon in 1853, he operated a farm in Polk County and was later the county’s judge.