| Election Name: | 1988 United States Senate election in Connecticut |
| Country: | Connecticut |
| Type: | presidential |
| Ongoing: | no |
| Previous Election: | 1982 United States Senate election in Connecticut |
| Previous Year: | 1982 |
| Next Election: | 1994 United States Senate election in Connecticut |
| Next Year: | 1994 |
| Election Date: | November 8, 1988 |
| Image1: | File:Joe Lieberman.jpg |
| Nominee1: | Joe Lieberman |
| Party1: | Democratic Party (United States) |
| Popular Vote1: | 688,499 |
| Percentage1: | 49.91% |
| Nominee2: | Lowell Weicker |
| Party2: | Republican Party (United States) |
| Popular Vote2: | 677,903 |
| Percentage2: | 49.15% |
| U.S. Senator | |
| Before Election: | Lowell Weicker |
| Before Party: | Republican Party (United States) |
| After Election: | Joe Lieberman |
| After Party: | Democratic Party (United States) |
The 1988 United States Senate election in Connecticut took place on November 8, 1988. Incumbent Republican U.S. Senator Lowell Weicker ran for re-election to a fourth term, but was narrowly defeated by Democrat Joe Lieberman, the Connecticut Attorney General and eventual 2000 nominee for Vice President of the United States, who would remain in office until 2013. This is the last time a Connecticut Senator lost re-election.
Both Weicker and Lieberman would go on to win state-wide elections as independents, in 1990 for governor and in 2006 for Senate respectively. Joe Lieberman's swearing-in marked the first time since 1971 that Democrats held both Senate seats from Connecticut.
Lieberman was often considered to the right of Weicker, with him benefiting from the support of National Review founder William F. Buckley Jr., and his brother, former U.S. Senator from New York James Buckley, with William Buckley running columns in support of Lieberman.