Arnold Williams (May 21, 1898 – May 25, 1970) was an American politician and businessman who served as the 21st governor of Idaho from 1945 until 1947.

Born in Fillmore, Utah, Williams attended its public school and Henagers Business College in Salt Lake City.

Following his discharge, he established a successful dry cleaning business in Rexburg, Idaho.

He finished the unexpired term of Charles Gossett, who resigned after ten months and was immediately appointed by Williams to the U.S. Senate seat left vacant by the death of Republican John Thomas.

[7][8][9] The first Mormon to be elected as Idaho's governor was incumbent Democrat John Evans in 1978.