William Howard Thompson (October 14, 1871 – February 9, 1928) was a United States senator from Kansas.

He was the official court reporter of the twenty-second judicial district of Kansas from 1891 to 1894, and studied law; he was admitted to the bar in 1894, commencing practice in Seneca; he was clerk of the Kansas Court of Appeals in Topeka and practiced law there from 1897 to 1901.

He was defeated by 30 percentage points, the largest loss ever by a sitting U.S. senator not running as a third-party candidate.

[1] While in the Senate, he was chairman of the Committee on Expenditures in the Departments of Commerce and Labor (Sixty-third Congress) and a member of the Committee on Expenditures in the Department of Commerce (Sixty-third and Sixty-fourth Congresses) and the Committee to Audit and Control the Contingent Expenses (Sixty-fifth Congress).

He moved to Washington, D.C., in 1927, where he continued the practice of law, and died there in 1928, aged 56.