1916 United States Senate election in Pennsylvania

The 1916 United States Senate election in Pennsylvania was held on November 7, 1916. Incumbent Republican U.S. Senator George T. Oliver was not a candidate for re-election.

The Republican nominee, Philander C. Knox, defeated Democratic nominee Ellis C. Orvis.

Candidates

 * Herbert T. Ames, Williamsport attorney (Prohibition)
 * Charles W. Ervin (Socialist)
 * Philander C. Knox, former U.S. Senator and United States Secretary of State (Republican)
 * Robert Colvin Macauley Jr. (Single Tax)
 * Ellis L. Orvis, Bellefonte attorney and retired Centre County judge (Democratic)
 * William H. Thomas (Socialist Labor)

Aftermath
Knox subsequently died in October 1921, during his first term, and William E. Crow was appointed to fill the vacancy. Crow then also died before the expiration of the term, in August 1922.

David A. Reed was then appointed to fill the vacancy created by Crow's death, and was subsequently elected to complete the rest of the term expiring in March 1923 and to a full six-year term in his own right on the same day.