William Harvey Johnson Ely (September 8, 1891 – March 2, 1942) was an American jurist and Democratic Party politician from New Jersey who served as a State Senator and the state administrator for the Works Progress Administration.
His father was a leading lawyer and Democratic politician in Rutherford who had moved from Westfield, Massachusetts, where the family had long-standing ties.
He served as a lieutenant in the National Guard on the Mexican border in 1916 and was with the United States Army Motor Transport Corps during World War I.
He married Mary E. Rogers of Paterson, New Jersey on April 30, 1917, and they had three sons and two daughters.
In the 1938 election he faced Republican William Warren Barbour, who had served in the Senate from 1931 to 1937.