William Helmus Holliday (May 21, 1843 – February 20, 1925) was an American politician who served in the territorial and statehood Wyoming Legislature as a member of the Democratic Party.

In September 1867, he moved to Albany County, Wyoming Territory while working at a sawmill.

[1] On May 5, 1869, Holliday married Emily R. Coykendall and had three children with her; their marriage lasted until her death on June 19, 1887.

On January 9, 1884, Robert H. Homer made a motion to have Holliday selected as President of the council and it was accepted.

[1] During the 1882 elections, he ran as a candidate for Wyoming's delegate to the United States House of Representatives.