Willis Van Devanter (April 17, 1859 - February 8, 1941), associate justice of the United States Supreme Court, January 3, 1911 to June 2, 1937.

Born in Marion, Indiana, he graduated from the University of Cincinnati College of Law in 1881. After three years private practice in Marion, he moved to the Wyoming Territory where he served as city attorney of Cheyenne, Wyoming, a member of the territorial legislature, as as chief judge of the territorial court. Upon statehood, he again took up private practice including much work for the Union Pacific and other railroads. In 1903, Theodore Roosevelt appointed him to the Eighth Circuit Court of Appeals, and William Howard Taft elevated him to the Supreme Court in 1910, where he served until his death.

On the court, he made his mark in opinions on public lands, Indian questions, water rights, admiralty, jurisdiction, and corporate law, but is best remembered for his opinions defending limited government in the 1920s and 1930s. He voted against the Agricultural Adjustment Administration (United States v. Butler), the National Recovery Administration (Schechter Poultry Corp. v. United States), federal regulation of labor relations (National Labor Relations Board v. Jones and Laughlin Steel Corp. ), the Railway Pension Act (Railroad Retirement Board v. Alton Railroad ), unemployment insurance (Steward Machine Co. v. Davis ), and the minimum wage (West Coast Hotel v. Parrish). For his conservatism, he, along with Pierce Butler, James Clark McReynolds, and George Sutherland was known as one of the Four Horsemen.

He died in Washington, D.C. and was buried there in Rock Creek Cemetery.