| Election Name: | 1984 United States Senate election in Montana |
| Country: | Montana |
| Type: | presidential |
| Ongoing: | no |
| Previous Election: | 1978 United States Senate election in Montana |
| Previous Year: | 1978 |
| Next Election: | 1990 United States Senate election in Montana |
| Next Year: | 1990 |
| Election Date: | November 6, 1984 |
| Image1: | Max Baucus 1977 Congressional photo.jpg |
| Nominee1: | Max Baucus |
| Party1: | Democratic Party (United States) |
| Popular Vote1: | 215,704 |
| Percentage1: | 56.89% |
| Nominee2: | Chuck Cozzens |
| Party2: | Republican Party (United States) |
| Popular Vote2: | 154,308 |
| Percentage2: | 40.70% |
| U.S. Senator | |
| Before Election: | Max Baucus |
| Before Party: | Democratic Party (United States) |
| After Election: | Max Baucus |
| After Party: | Democratic Party (United States) |
The 1984 United States Senate election in Montana took place on November 6, 1984. Incumbent United States Senator Max Baucus, who was first elected in 1978, ran for re-election. He easily won renomination in the Democratic primary, and advanced to the general election, where he faced Chuck Cozzens, a former State Representative and the Republican nominee. Despite President Ronald Reagan's strong performance in the state that year, Baucus was able to easily win a second term over Cozzens.