1942 United States Senate elections

The 1942 United States Senate elections were held November 3, 1942, midway through Franklin D. Roosevelt's third term as president. The 32 seats of Class 2 were contested in regular elections, and two special elections were held to fill vacancies.

Although this election took place during World War II, the opposition Republican party made major gains, taking eight seats from the Democrats and one from an independent. Though the Democrats retained a significant majority, it was the smallest since Roosevelt was first elected in 1932. The Republican gains also erased the Democratic supermajority that they held since 1932. Democrats later gained a seat in New Jersey through an appointment, bringing their seat total up to 58.

The New York Times ascribed the results to "voters' dissatisfaction with the conduct of the war, both at home and abroad" but not evidence of a lack of enthusiasm for the war effort. It found that a candidate's stance as an isolationist or an interventionist before the Attack on Pearl Harbor (December 1941) had little impact on his success at the polls. The paper's editorial board welcomed a return to normal political alignments after the unbalanced majorities of the previous decade. The election not only changed the numbers of Democrats and Republicans in the Senate, but also accomplished an ideological shift, as several longtime enthusiastic supporters of the New Deal were replaced by Republicans of the most conservative sort.