The Dyer Anti-Lynching Bill (1918) was first introduced in the 65th United States Congress by Representative Leonidas C. Dyer, a Republican from St. Louis, Missouri, in the United States House of Representatives as H.R. 11279 in order “to protect citizens of the United States against lynching in default of protection by the States.” It was intended to establish lynching as a federal crime. The Dyer Anti-Lynching Bill was re-introduced in subsequent sessions of United States Congress and passed, 230 to 119, by the House of Representatives on January 26, 1922, but its passage was halted in the United States Senate by a filibuster by Southern Democrats, who formed a powerful block. Southern Democrats justified their opposition to the bill by arguing that lynchings were a response to rapes and proclaiming that lynchings were an issue that should be left for states to deal with.

Leonidas Carstarphen Dyer was an American politician, reformer, civil rights activist, and military officer. A Republican, he served eleven terms in the U.S. Congress as a U.S. Representative from Missouri from 1911 to 1933. In 1898, enrolling in the U.S. Army as a private, Dyer served notably in the Spanish–American War; and was promoted to colonel at the war's end.