The 1976 United States Senate election in Montana took place on November 2, 1976. Rather than seek a fifth term, incumbent United States Senator
Mike Mansfield, a
Democrat, opted to retire, creating an open seat. United States Congressman
John Melcher, who had represented
Montana's 2nd congressional district from 1969 to 1977, won the
Democratic nomination and defeated Stanley C. Burger, the
Republican nominee, by a wide margin in the general election. This was the first open seat election in Montana since
1960 and the first open seat election in Montana for the Class 1 Senate seat since
1922.