William Ellery Sweet (January 27, 1869 – May 9, 1942) was an American banker and politician who served as the 23rd Governor of Colorado from 1923 to 1925.

He also excelled playing quarterback for the college football team and was a member of Phi Kappa Psi fraternity.

He decided to start up an investment banking firm, which led the Sweet family to become wealthy, and even let William retire in 1922.

He was a fierce opponent of the Ku Klux Klan and attributed his loss in the 1924 election to this opposition when he lost to Klansman and Republican nominee Clarence Morley, who ran with the support of the then-politically powerful Ku Klux Klan.

[2] In 1924, after initially supporting McAdoo, he became a "favorite son" candidate for the Colorado delegation at the 1924 Democratic National Convention.