| Election Name: | 1984 United States Senate election in Maine |
| Country: | Maine |
| Type: | presidential |
| Ongoing: | no |
| Previous Election: | 1978 United States Senate election in Maine |
| Previous Year: | 1978 |
| Next Election: | 1990 United States Senate election in Maine |
| Next Year: | 1990 |
| Election Date: | November 7, 1984 |
| Map Size: | 300px |
| Image1: | Senator William Cohen (R-ME).jpg |
| Nominee1: | William Cohen |
| Party1: | Republican Party (United States) |
| Popular Vote1: | 404,414 |
| Percentage1: | 73.34% |
| Nominee2: | Libby Mitchell |
| Party2: | Democratic Party (United States) |
| Popular Vote2: | 142,626 |
| Percentage2: | 25.87% |
| U.S. Senator | |
| Before Election: | William Cohen |
| Before Party: | Republican Party (United States) |
| After Election: | William Cohen |
| After Party: | Republican Party (United States) |
The 1984 United States Senate election in Maine was held on November 7, 1984. Incumbent Republican U.S. Senator William Cohen won re-election to a second term in a landslide.