| Election Name: | 1966 United States Senate election in Delaware |
| Country: | Delaware |
| Type: | presidential |
| Ongoing: | no |
| Previous Election: | 1960 United States Senate election in Delaware |
| Previous Year: | 1960 |
| Next Election: | 1972 United States Senate election in Delaware |
| Next Year: | 1972 |
| Election Date: | November 8, 1966 |
| Image1: | File:BoggsCaleb.jpg |
| Nominee1: | J. Caleb Boggs |
| Party1: | Republican Party (United States) |
| Popular Vote1: | 97,268 |
| Percentage1: | 59.12% |
| Party2: | Democratic Party (United States) |
| Popular Vote2: | 67,263 |
| Percentage2: | 40.88% |
| Map Size: | 210px |
| U.S. Senator | |
| Before Party: | Republican Party (US) |
| After Party: | Republican Party (US) |
The 1966 United States Senate election in Delaware took place on November 8, 1966. Incumbent Republican U.S. Senator J. Caleb Boggs was re-elected to a second term in office, defeating Democratic nominee James M. Tunnell Jr., this is the last time Republicans won Delaware's Class 2 Senate seat.