William Henry King (June 3, 1863 - November 27, 1949) was an American lawyer, jurist, and statesman from Salt Lake City, Utah. He represented Utah in the United States Senate from 1917 until 1941. He was a Democrat.
King was born in Fillmore, Utah in 1863. He went to Brigham Young University in Provo, Utah and the University of Utah at Salt Lake City. He was the associate justice of the Utah supreme court between 1894 and 1896. He was elected to the 55th Congress and served between March 4, 1897 and March 3, 1899. He did not get renominated in 1898. But he was elected again to fill the unseating of Brigham H. Roberts and served between April 2, 1900 and March 3, 1901. He ran for reelection in 1900 and again in 1902, but lost both times.
He was then elected four times to the Senate and served between March 4, 1917 and January 3, 1941. He served as the President pro tempore of the Senate during the Seventy-sixth Congress.
He returned to Utah and died there in 1949. His son, David S. King, also served in Congress.