| Election Name: | 1966 United States Senate election in Tennessee |
| Country: | Tennessee |
| Type: | presidential |
| Ongoing: | no |
| Previous Election: | 1964 United States Senate special election in Tennessee |
| Previous Year: | 1964 (special) |
| Next Election: | 1972 United States Senate election in Tennessee |
| Next Year: | 1972 |
| Election Date: | November 8, 1966 |
| Image1: | Howard Baker photo.jpg |
| Nominee1: | Howard Baker |
| Party1: | Republican Party (United States) |
| Popular Vote1: | 483,063 |
| Percentage1: | 55.72% |
| Nominee2: | Frank G. Clement |
| Party2: | Democratic Party (United States) |
| Popular Vote2: | 383,843 |
| Percentage2: | 44.27% |
| Map Size: | 300px |
| Senator | |
| Before Election: | Ross Bass |
| Before Party: | Democratic Party (United States) |
| After Election: | Howard Baker |
| After Party: | Republican Party (United States) |
The 1966 United States Senate election in Tennessee was held on November 8, 1966, concurrently with other elections to the United States Senate in other states as well as elections to the United States House of Representatives and various state and local elections. Republican nominee Howard Baker won the election, defeating Democratic nominee and Tennessee Governor Frank G. Clement with 55.7% of the vote.
In the primary, incumbent Democratic Senator Ross Bass lost to Governor Clement by a little over 2%.
Baker became the first Republican to represent Tennessee since the temporary appointment of Newell Sanders in 1912. He was the first Tennessee Republican to win a full term in the Senate since Reconstruction in 1867 and the first ever to win a popular election to the Senate. He was also the first Republican to win a full term to this Senate seat.