The United States Senate election of 1916 in New Jersey was held on November 7, 1916. Incumbent Democratic Senator James E. Martine ran for re-election to a second term in office, but was defeated by Republican State Senator Joseph S. Frelinghuysen Sr. Primary elections were held on September 26. Senator Martine defeated a challenge from John W. Wescott, the Attorney General of New Jersey and an ally of President Woodrow Wilson. The Republican nomination narrowly went to State Senator Joseph S. Frelinghuysen Sr. over former Governor Franklin Murphy.