William Hitz (April 21, 1872 – July 3, 1935) was a United States federal judge.
Born in Washington, D.C., Hitz received his undergraduate education from Harvard College, and received an LL.B from Georgetown University Law School in 1900. He was in private practice in Washington, D.C. from 1900 to 1914. He was a Special attorney of the U.S. Department of Justice in Washington, D.C. from 1914 to 1916.
On November 15, 1916, Hitz received a recess appointment from President Woodrow Wilson to a seat on the United States District Court for the District of Columbia vacated by Thomas H. Anderson. Formally nominated on December 15, 1916, Hitz was confirmed by the United States Senate on January 2, 1917, and received his commission the same day. Hitz served in that capacity until February 13, 1931, due to appointment to another judicial position.
On January 5, 1931, Hitz was nominated by President Herbert Hoover to a new seat on the United States Court of Appeals for the D.C. Circuit created by 46 Stat. 785. He was confirmed by the United States Senate on January 28, 1931, and received his commission on February 6, 1931. Hitz served in that capacity until his death.