The 1942 United States Senate election in Montana took place on November 3, 1942. Incumbent United States Senator
James E. Murray, who was first elected to the Senate in a special election in
1934 and was re-elected in
1936, ran for re-election. Following his victory in a competitive
Democratic primary, Murray advanced to the general election, where he was opposed by former
United States Attorney for the District of MontanaWellington D. Rankin, the
Republican nominee and brother of representative
Jeannette Rankin. In a closely fought election, Murray narrowly defeated Rankin to win re-election to his third term and his second full term in the Senate.