| Election Name: | 1966 United States Senate election in Wyoming |
| Country: | Wyoming |
| Type: | presidential |
| Ongoing: | no |
| Previous Election: | 1962 United States Senate special election in Wyoming |
| Previous Year: | 1962 |
| Next Election: | 1972 United States Senate election in Wyoming |
| Next Year: | 1972 |
| Election Date: | November 8, 1966 |
| Image1: | Clifford Hansen.jpg |
| Nominee1: | Clifford Hansen |
| Party1: | Republican Party (United States) |
| Popular Vote1: | 63,548 |
| Percentage1: | 51.80% |
| Nominee2: | Teno Roncalio |
| Party2: | Democratic Party (United States) |
| Popular Vote2: | 59,141 |
| Percentage2: | 48.20% |
| Map Size: | 255px |
| U.S. Senator | |
| Before Election: | Milward Simpson |
| Before Party: | Republican Party (United States) |
| After Election: | Clifford Hansen |
| After Party: | Republican Party (United States) |
The 1966 United States Senate election in Wyoming was held on November 8, 1966. First-term Republican Senator Milward Simpson, who was first elected in the 1962 special election, declined to seek re-election because of his declining health.[1] Governor Clifford Hansen won the Republican primary and faced Democratic Congressman Teno Roncalio in the general election. Despite the strong performance by Republicans nationwide, and the strong Republican victory in the gubernatorial election, the race was quite close. Hansen ended up winning, defeating Roncalio with 52% of the vote.