1940 United States Senate election in Wyoming

The 1940 United States Senate election in Wyoming took place on November 5, 1940. Democratic Senator Joseph C. O'Mahoney ran for re-election to a second full term. He faced Republican Milward Simpson, a member of the University of Wyoming Board of Trustees and a former State Representative, in the general election. Though the presidential election in Wyoming was relatively close, O'Mahoney outperformed President Franklin D. Roosevelt's narrow win, and defeated Simpson in a landslide to win his second term.

Candidates

 * Joseph C. O'Mahoney, incumbent U.S. Senator
 * Cecil W. Clark, former Weston County Prosecuting Attorney

Candidates

 * Milward Simpson, member of the University of Wyoming Board of Trustees, former State Representative
 * Harry B. Henderson, Jr., State Senator
 * Charles E. Winter, former U.S. Congressman
 * Irving W. Dinsmore, former State Senator
 * R. R. Crow, State Representative