Thomas S. Martin(as Conference Chairman) Democratic Henry Cabot Lodge(Unofficial) Republican The 1918 United States Senate elections were held throughout 1918,[a] the midpoint of Woodrow Wilson's second term as president.

This was the first election since the ratification of the 17th Amendment that all 32 Class 2 senators were subject to direct or popular election, making them the final class under the old system of being selected by state legislatures.

Republicans gained a slim 2-seat control after picking a net of 6 seats up.

Eight Democrats and one Republican sought re-election but lost in the primary or general election.

One Democrat died on October 21, 1917, and his seat remained vacant until an April 1918 election.