| Election Name: | 1966 United States Senate election in Montana |
| Country: | Montana |
| Flag Year: | 1905 |
| Type: | presidential |
| Ongoing: | no |
| Previous Election: | 1960 United States Senate election in Montana |
| Previous Year: | 1960 |
| Next Election: | 1972 United States Senate election in Montana |
| Next Year: | 1972 |
| Election Date: | November 8, 1966 |
| Image1: | File:Lee Warren METCALF.jpg |
| Nominee1: | Lee Metcalf |
| Party1: | Democratic Party (United States) |
| Popular Vote1: | 138,166 |
| Percentage1: | 53.17% |
| Nominee2: | Tim Babcock |
| Party2: | Republican Party (United States) |
| Popular Vote2: | 121,697 |
| Percentage2: | 46.83% |
| U.S. Senator | |
| Before Election: | Lee Metcalf |
| Before Party: | Democratic Party (United States) |
| After Election: | Lee Metcalf |
| After Party: | Democratic Party (United States) |
The 1966 United States Senate election in Montana took place on November 8, 1966. Incumbent United States Senator Lee Metcalf, who was first elected to the Senate in 1960, ran for re-election. He won the Democratic primary uncontested, and moved on to the general election, where he was opposed by Tim M. Babcock, the Republican nominee and the Governor of Montana. Though the race remained close, Metcalf was able to expand on his 1960 margin of victory, and defeated Babcock to win a second term.